Magic Bullet does what it does well, but it is pricey. Currently it is available for after effects and they came out with a plugin for final cut. I believe i heard premiere pro will come soon.
It depends what you want to do - MB is an exceptional color corrector, especially if you dont like to deal with tweaking color - it runs like a color correction wizard. It also features mattes and a deinterlacer. But obviously the biggest reason to use it is the frame rate conversion, which is only available in the after effects version. Well, it does do a decent job, but there is a whole list of things they suggest you do differently when filming to achieve the best output, so for existing projects you may not get perfect results. The biggest problem is the time it takes for MB to process, literally hours for a few minutes of video.
IF you have that kind of time AND a true need for changing your frame rate, then yea, consider it. But if you are just trying to juice up the look of your video, check out their comparison:
http://www.redgiantsoftware.com/magicbulletfamily.htmlI'd say the final cut version is a good deal at 299, if that is doing what you are looking for. The frame rate conversion is really a benefit more if you are transferring to film, if you want to make your video look like film, then use the tools for color and saturation and such. they do a good job. They offer a demo, so check it out.