Two magi in my game have learned this spell. They are now fond of grabbing small stones while in foreign lands, and then using the spell to travel from Aquitaine to Baghdad in the blink of an eye. While "travelling" with the main group in the far East, they would pop back to their laboratories in France and continue their labwork, only meeting up with the traveling party to make sure they were not needed. When the group was stranded by sandstorms in Baghdad for a season, these two magi were able to return home to relax and use their labs while the others worked in suboptimal conditions. Not a complaint of unfairness but just a note of how the spell is used.
The arcane connections to France they have been collecting will soon stop working due to an interesting story element - the lands of kingless France are changing, and the sudden inability of Leap of Homecoming to return to France highlights a broader metaphysical issue that the group will need to investigate. The France of two years ago is not the France of today.
However, overall, I'm a bit wary of what this might mean to the Order of Hermes as a whole - it feels as if it detracts from the "medievalness" of the setting to have instant and relatively easy transport across such vast differences. I have the same feeling when discussion veers towards magical cell-phones or similar.
Yet, on the other hand, it is definitely magical.
How have others dealt with Leap of Homecoming in their game?
Do you do any house rules or accept it as is? Are there any aspects of the spell I am overlooking?
Thanks in advance! We're in our third year of our Ars Magica saga and we're having a great time!