Even The Urbz (sucked) was better than the GBA version just for the touch screen support in the minigames and navigation. A game like The Sims doesn't rely heavily on the graphics. The only version I'd find more appealing would be the PC version.
With that said, I won't be buying it on any format.
Personally I'm more interested in the PSP version as that actually looks nice. Hmm, wonder if it has downloadable content. I'm not a fan of the StrangeTown neighborhood though :/