I want one of these and I considered the mag fed, I read some bad reviews about them cycling bad and ####ty quality, and here is what makes me lean towards the tube mag.. You can just keep loading shells into the bottom of it constantly, shoot one when you need it and right away put one back in, or dump the one in the chamber and the tube and not have to remove anything to reload it. It only holds 2, but it's not hard to reload. Not saying the mag fed one is either.
All depends on your preference/what your using it for I guess!