I've had my PSP for about 10 days now and I've had my eye on Metal Gear Ac!d for some time now, so I got it. After beating it tonight I have to say that this game was simply amazing. I've never been a big card battle enthusiast and I've only dabbled in the Metal Gear series (played some of Metal Gear Solid and some of the GBC game) so I wasn't put off by the new style.
There were somethings about the game that I didn't like: I didn't like the lack of colors (fixed in the sequel), I didn't like the lack of voice acting and I didn't like losing your turn when your movement triggers a movie. However, other than that I thought the game was definitely something that shouldn't be missed. I can't wait to play the sequel.