Chozo: I barely play it primarily for two reasons. The first is that the controls are a joke, especially with the whole "the square button is off center and it feels like you'll break it if you press it there wrong way" thing. (Note: I think it is the square button....it's the "west" one.) Second is that my battery is officially dead, and I'm lucky to get any playtime at all out of it. (Sadly, this is now the case with my launch DS as well - it gets maybe 2-3 hours on a full charge these days.) I've heard the Slim helps alleviate both of those, both with the physical construction and improved battery life. I think I read somewhere that the system also has a small amount of RAM devoted entirely to loading game data, which seems like a smart thing on Sony's part.
IceCold: Ho ho! And indeed I am! I've a gift certificate that I debate using toward the purchase of a Slim. Either that or I'll buy a used one off a user on that site. Besides, selling my original means that I can upgrade for ....at the most, I'm thinking 40-50 bucks, all things considered, which is satisfying. Besides, I'm something of a technophile, so I don't mind getting the best version of something available (though I still lack a DSLite, but that's because I keep holding out for a Navy one, which doesn't look like it will happen until I ultimately make it over to Japan).
The PSP could have been really great. Could have been. All it has ended up being is a system with some really nice multimedia features and a few choice games that I'd rather play on the PS2.