Awesome feedback everyone, thanks.
Heckler: Point taken about Class III hitch, I will definitely look out for that.
Taprider: I'm just going by online info, 36 cu ft cargo room w/ my Legacy vs 22 cu ft for 08 Matrix.
What I'd love to know is if I can chuck my XS road bike in the back with rear seats up (front wheel off).
We have a 2008 Forester, and a 2007 Vibe, and in terms of size, the rear cargo space is a little shorter on the vibe, but there's more leg room than the forester. Overall the vibe has more headroom and I would say it has the same total storage space, just in different ratio to the (slightly longer) forester. I can fit a MTB in the back without taking the wheels off.
The vibe has been awesome, handles well, not the fastest (but that's irrelevant for 99% of city driving), and it's really, really comfy.
Like Heckler, we didn't even bother looking at the Matrix, since the Vibe is identical, but a lot less money, and IMO looks better.