Man, everyone is getting Softshells these days! Read the last few threads about Softshells. They can give you an idea of what you could be getting yourself into!
Lots of people buy them but you also need to think of all the things they need. The most important thing to look at is their max size. I'm not sure how someone can manage a 3 foot long Asian Softy but if you can, more power to you...
These are one of the most difficult turtles to keep. They need very clean water even more so than some fish. They are also to be kept by themselves, found this out the hard way. I started out with 8, 4 males and 4 females at the end of a six month span i only had 1 male, the others killed eachother they were 3 inch babies, Adults will kill eachother in a matter of days. Also they are carnivores and alot of turtle pellets have plant matter in them because they are generalized for the most common of turtle the red ears. I fed mine ghost shrimp when they were little and the one that killed everybody else at crayfish and clams when he was an adult. Imo I wouldnt get a soft shell, They are alot of work and are not your normal turtle. This turtle will cost you lots of money, even though they sell them for 10 bucks at reptile shows.
I'm not sure which soft-shell are we talking about here, but I've had one for around 7 months now (he's around 5" across) and he's quite happy in an outdoor tank with a slightly larger RES. They enjoy natural sunlight, and while the water is not filtered, its swirled by a 200GPH submersible to discourage algal buildup. They both eat all kinds of pellets, shrimp, krill, silversides and livebearers (if they can catch them). I do a 100% W/C every 3 weeks. I'll try to post pics soon.