I was sitting on my hands and hoping that when the Nintendo DS launched, as the clear underdog, it would surprise everyone and stand up to the PSP quite well.
Being half the price was already making it attractive and a safer investment. Likewise, the idea of dual screens and backwards compatability had me daydreaming of the possibilities.
Unfortunately, I've learned that the DS only supports GBA games, and its compatability doesn't stretch back to the original GameBoy games. That's a big punch, since the last Nintendo product I bought was a gameboy, and I was holding out for being able to use my stack of cartridges on the DS. No go.
After playing around with the system at shop displays, the unit feels tacky, too. A real low-quality feel to the buttons and especially the wimpy D-Pad. The styling is horrible. All-silver and cheap plastic construction, coupled with considerable size, makes this a far inferior product to the GBA: SP (of which the NES version looks like an attractive purchase right now).
The touchpad.. nice idea, essentially gives the DS the potential to be used as a PDA as well. Unfortunately, it doesn't come with and kind of email, calender or contacts facility, just chat... Maybe in the future, but that would mean paying for features which could easily come as standard

Lastly, the dual screen hasn't been taken advantage of in the way I'd hoped. Granted, it's early days, but it looks like it's only ever going to be able to push basic 2d images, as opposed to, say, being able to view your teammates screen on HIS DS when you link up for some co-op action.
However for all the faults of the DS, the end result doesn't make me want to purchase a PSP, at least not yet. I can live without mobile gaming for the forseeable future, and if anything does tempt me, it's likely to be the GBA: SP dropping in price over the coming months.
How about everyone else who's considering the new kit? What's your thoughts?