I haven't started Phoenix Wright yet. So few adventure games come out for the DS, I like to savor them, so I probably won't start that one until I've finished Hotel Dusk. (I played the first PW game in bits and pieces over nine months!)
Regarding the DS in general, it is a wonderful system and totally worth buying. I don't own any other console but I love my DS. It is great to travel with and to play while lying around on the couch.