Venditor (HoH: Mystery Cults) is terrible. It's a Major Social virtue that gives you 50XP and access to Academic Abilities - note the 50XP you get can't be spent on academic abilities, but on Bargain, Guile, etc.
Wise One is the weakest of the Minor Social Virtues, as it offers little aside from access to either Arcane or Academic Abilities - it says you're respected locally, but that to my mind means a Reputation, which it does not give.
Wilderness Sense is terrible - probably always better off buying Puissant Survival, given Survival is more broad, unaffected by Aura, and strictly speaking still necessary even to a character with Wilderness Sense.
Hermetic Prestige gives Reputation of 3. Famous gives Reputation 4. There is no reason you can't be Famous with the Order of Hermes.
Magical Memory generally sucks. If you made something before, odds are you don't need the lab text to reproduce it. This only becomes useful for Charged Items (so you can make lab total/5 charges rather than just one), and then only if you've lost your old lab text.
Mythic Blood is bad because it's a Major Hermetic virtue and you're only allowed one of them. You could get a Minor Magical Focus and a special magical power* (RoP: Magic) as Minor Virtues, so the only thing it truly offers is no fatigue loss for missing a Formulaic Spell by less than 10 points. While the sum of its parts are equal to +3, the fact that it restricts you from getting some other Major Hermetic Virtue makes it a bad choice.
Flexible Formulaic Magic, Flawless Magic, Life Linked Spontaneous Magic, all no brainers.
Unaging is stupid good for magi. Never lose characteristic points, never become enfeebled. Even if you assume that magi compensate with stat boosting spells as they age, this saves you a ton of vis over time, or that vis could go to making you even better instead of shoring up your characteristics.
Skilled Parens is very good if you're building a magi fresh out from Gauntlet. Those 60xp and 30 spell levels make a huge difference.
Second Sight is unreliable but simulates a ton of Intellego spells and doesn't need to penetrate Magic Resistance. It's also one of the more common Supernatural Virtues so may sources of learning (teachers, books) should be available.
Mechanically, Puissant is better than Affinity until an Ability or Art gets pretty high. As others have pointed out, combining both of them is even more powerful.
Personal Vis Source means you never have to scrounge for your favorite vis - you'll never have enough, of course, but you'll always have some.
Minor Magical Foci are great. Major Magical Foci are usually hard to fully exploit for their point cost.
Life Boost is great when you really need a high casting total.
Enduring Magic is pretty potent if you're a ritualist. Your Aegis of the Hearth could last 10 years - come to think of it, this is way more powerful than Mercurian Magic, though only if you concentrate on long duration rituals.
Cautious Sorcerer...people would still take it if it was only 2 fewer botch dice, and it's THREE.
Book Learner means even crappy tractatus are worth reading.