I have it as well. Before Alakazam's finrot started progressing I had him in that same kit and when the filter stopped working (I fixed it there was just hair twisted around the propeller) he made a big bubblenest! =] He loved it. He really wants to be back in it! You;ll have to make a baffle because the current is really strong for a betta. That's like 2 minutes work tops though. =]
Should be fine if you can baffle the filter and add an adjustable 25Watt heater. The description does not say if it has incandescent or fluorescent lighting in the hood, though. If it is incandescent, you will have to replace the bulbs with compact fluorescent ones--incandescents get way too hot and cause dangerous temperature fluctuations.
Remember to do a fishless cycle on the tank before you put your fish in. :)