Wolfpup, yeah, I still have my GBA SP for regular GBA games, so no worries on that front.(Except I do seem to have misplaced the charger).
I went to GS near opening this morning and there weren't many people there. I got unit card #7, so I assume they had only sold 7 up till the point I got there (because I preordered way late so I definitely wasn't preorder #7). Anyway, the guy at the GS said they had a lot of preorders but only got 2 units that weren't preorders. I was at Target and Best Buy today too and they had plenty of units out for sale so I don't think anyone would have a problem finding one.
I did trade in my DS Lite, even though it was hard for me to to do! I had an original launch unit, plain white, good condition but I'm not sure I would have gotten much more than $50 on it for eBay if I'd tried selling it later.
Now, playing regular DS games on the 3DS.... obviously, I don't have my Lite here to compare it to directly anymore... but just putting a game in, and playing in the mode with the black bars on the left and right sides (which mine did automatically), the games look okay. So, even on the default setting, mine is not stretching the game to fill the whole screen so maybe that's why it doesn't look too bad. The text looks decent, but yeah, it might be a little more blurry. Then, this is still a DS we're talking about - no DS has stellar graphics. (It's not like it has a Retina Display!). When I ran the game in native resolution (holding down the start and select when selecting the game) it IS rather small...probably too small for my tastes. So larger and fair or smaller and more clear - yeah, I guess it's just what everyone has said. Load times aren't bad, but quitting times are a little longer. (and the game I tested this on was Okamiden).
I did check for an update when I turned the 3DS on and it ran and said it was updating something - I have no idea what?
I got the Monkeyball game, but I'm not that into it so I haven't opened it yet - just had a Target gift card so I thought I'd use it on a game... but I kind of feel like returning it and waiting until the prices drop on the launch games. $40 is too much for any of them, imo. Even the decent ones are short in length or remakes of old games...all seem to have a problem or two.