GPS questions

Background... newly minted PPL, looking to ease navigation via GPS. I
actually find it cool to navigate via maps, compass and timepiece, but I
realize there is a lot more capability out there.

I'll be renting for awhile, so portability is important. I've done the
standard research (including searching prior posts on this newsgroup), but
still have a few questions that remain unanswered.

The Garmin 396 looks pretty awesome. I don't know if I'll fly enough to
warrant the Wx subscription, but I have a healthy respect for weather and so
lean towards it for the additional security.

The only downside I see in the 396 is screen size. I like what I've seen of
the Avmap (Jay... figure I can count on your endorsement here, based on
reading past postings). I think all it's missing vs. the 396 is weather.
Would be interesting to know if anyone has heard if this will be a soft
upgrade in the future. Also, I believe the Avmap is direct powered from the
plane, and I don't know if and how this will be possible on rental aircraft.
Any insight?

I've also run into the Flight Cheetah in my searches, though haven't found
much talk about it on the newsgroups. It seems to have everything, but I
hesitate to be a "test pilot" being a neophyte at flying to start with.

I won't say cost isn't an issue, but I have room enough to spare to pretty
much get whatever portable is best. I welcome any and all advice on the
issue. Thank you to all in advance.