The Twin Com certainly meets a lot my the criteria as well. But then, despite the fact that there is quite a community around this ship, I really don't like the fact that it is even older than the PA44 and there's no factory support. At some point in the future spare parts and maintenance will become an issue.
maybe irish seaplane may bring us up to speed about parts for the Twin Com. From an owner I know who sold his Twin Com about 3 years ago to upgrade to a turboprop I understood that the Twin Commanche as well as the normal commanche are both supported both by Piper as well as a Commanche Society with several shops who have large stock of parts.
I know that this is also true for other legacy products where the companies are sometimes a bit slow or don't exist anymore.
In any case, I would urge you to be careful with forum or worse club hut talk and talk to people who actually own them (not the ones who want to sell, but who operate them) they will be able to tell you pretty straight what the story is. Or talk to shops maintaining them. That goes for both the Twincom and the PA44.