I was wondering whether the rules for charged items are not slightly unbalanced. What do you think of this argument?
Usually a magus' lab total is significantly higher than his casting total due to boni provided by the lab, Magic Theory (often higher than the average result of the casting die) and (in the case of items) shape & material boni.
If a magus spends one season to work on a charged item he can for example instill an effect at a level of 2/3 of his lab total with a penetration of the same level. This is certainly more impressive than a spell he could have invented in one season, even more impressive than a spell he could cast with the same TeFo combination, but well, he invested 3 month of his live in this one shot artifact, so that's just fair.
But if the magus spends another season in his lab, the final level of the original effect doesn't matter – he just gets one charge for every five points of his lab total.
For example Darius of Flambeau would be able to acchieve a lab total of 66 (21(Pe) +15(Co)+3(Int)+3(aura)+5(MagicTheory)+5(shape&material boni)+1(lab quality)+4(lab specialisation Pe)+1(lab specialisation Co)+8(knows similar spell) for instilling a wand with 'The Clenching Grasp of the Crushed Heart' and a penetration of 52. The wand he could produce in the second season would be instilled with 13 charges of this effect. Even a dedicated hoplite like him doesn't kill on a daily base, so this 'Wand of Death' will probably be sufficient for a decade at least.
So, even a explicit field mage who is comparatively weak in Magic Theory for his age and (subsequently) doesn't really have a good lab gains a serious ammount of firepower for comparatively few sacrifices, he has not even boosted his lab total with the help of a familiar or apprentice, nor has he used experimentation. Imho these rules result in a situation where magic resistance soon becomes irrelevant in the confrontation between magi. Being the first to shoot is sufficient.
I admit that spending time in the lab should bring advantages to a mage, and I probably wouldn't argue if we were talking about an invested device, paid for with vis and enchanted over many seasons, but this seems too easy.
There's plenty of economy in the description you gave, and it does seem like there might be an advantage. The main loss seems that time spent in the lab is time lost on other projects. For example, if you're a Magus you could make that wand in a season, then in the next season you make it again with a labtext and get more versions.
Another magus decides to learn a deadly Perdo Corpus spell (such as the one being put in the wand, or another one that counts as being similar). Then spends the season after it getting spell Mastery and taking the advantage of improved resistance. This doubles his magic resistance against that spell or any spell or power that would be considered similar by the rules on page 101. Now his magic resistance (even if his Parma isn't so great) will likely be better than the Penetration of one of these 'Fire and Forget' magic items. And he has the advantage of always having this, he doesn't need an item (even if he's a Verditius) to get that benefit. Now, he doesn't need to fire first, he can carefully attack his assailant who relies on such items with his spells and Arts, which might not be as easily defended against.
Basically there's exploits all over the place. The magic item one is one of the most obvious, but there are certainly ways around it, and we haven't even gotten into the different Mysteries yet.
I've recently paid more attention to the charged items, I used to think they're just cheap alternatives of casting some meager spells, with a possibility to offer the grogs/companions a chance to survive something they normally would not (e.g. a potion of Lungs of the Fish).
For that wand you calculate a Lab Total of 66 for Darius. The magus is pretty much a one-trick pony, only good at killing. Also, the specialisation of his laboratory (+4 Pe, +1 Co) does take time, vis and money. In my opinion, he has done quite a bit to get where he is with his Perdo Corpus totals, and I think the player should be able to do that after all the hard work he has done for it. Even if he has a weapon of mass destruction with his hands, he has used two seasons just for making it. I wouldn't be too happy to see our gaming group running along, all waving those wands around, but then again, even the players have some responsibility in the stories, and they too need to think where their saga is going.
Bear in mind, that the wand does work only for one target per round. A creative SG will find dirty tricks he can use to disable the continuous use of this thing. Even low level spells like Spasms of the Uncontrolled Hand cast with decent Penetration will work wonders, as the good old Pit of the Gaping Earth at his feet, and that's only the spells cast by magi. Add in hordes of grogs, stealing faeries, curious apprentices and the wand-waving magus will still find himself in trouble.
One of the first observations made about the fifth edition rules when they came out was that charged items can get obscene amounts of penetration, and that lab texts can give you gobs and gobs of charged items.
I house rule penetration for charged items. I know that I'm not alone.
There's nowt wrong with giving a magus a bit of power. As has been pointed out, he's more than welcome to spend the seasons to invent a "device of many killing opportunities".
Others might, as noted, learn the effect as a spell. In the short term, the device may be better, but in the longer term the magus with the spell is perhaps a little more flexible.
As long as you understand that the parma magica is a pants defence if someone really wants to kill you, nothing wrong with high penetration items. parma is good because it reduces distrust between magi, not because it is anything like a substantial defence vs spells. A parma of 8 can easily be broken using charged items and/or mastered spells.
Hmm. [Edit - delete foolish comment missing the point. Ooops.]
His own casting score is +38, he has Penetration 7, and Mastery 2 with the penetration choice, so when casting the spell he might have a final penetration of 16 [die 6+casting bonus 38+Penetration (in Perdo) 7+Mastery 2+Aura 3]. Even if he gets hold of a one-hour arcane connection (stealing a scale with high-penetration ReAn invested device?), only a x5 multiplier due to sympathetic magic would make it worthwhile to cast the spell himself; that requires something like knowing the target's nickname, secret name, and daily horoscope. In other words, unless you are prepared to face an opponent using a magic item is superior to spellcasting (unless you invest raw vis - Darius can add +72 to his penetration with raw vis...).
The problem isn't with charged items, it is with magical items. Obtaining high penetration through magic items is boring. When wanting to slay the dragon, you should be trying to obtain arcane connections and information on him to increase your sympathetic magic. When the dragon assaults you on your covenant, you should be sending out your Penetration-maxed magus with a bundle of raw vis and hope he rolls high and doesn't botch, not push out your grog with the Wand of Dragonslaying.
I suggest decreasing the penetration to +1 per extra level for magic items. Even this will allow for Penetration 26 for Darius, more than he could manage by casting the spell on his own without raw vis.
All true words, but does it really matter? I think not.
Killing an opponent that you know is not that hard. Most stories will be about discovering who your opponent is, when he shows up and to get to him when his goonies are not around.
I halve the bonus for penetration of charaged items to 1 per level. I've considered the idea that Xavi mentioned above of +1 per level for lesser enchanted devices and invested devices and +0.5 per level with charged items but I haven't yet seen it in play.