Here is a link to the Bradley Forum -
http://forum.bradleysmoker.com/I have owned a Bradley since 2009 and I like it a lot. with that said, what are you looking to do with it?
A Bradley is good for low and slow cooking. It is also good for smoking sausage - some say you have to buy a controller to get the tight temp control for sausage but many bradley owners use as is and are satisfied.
The Bradley runs on a 500 watt heating element. This can be slightly underpowered if you are trying to cook 4 large butts. It will get the job done, but take a while. Many have modified theirs and added a second element. Others have not made any mods and are completely satisfied.
Summary - it is a good unit for low and slow cooking. I can't say how it is unmodified because I added a PID controller and 2nd element from the beginning. With those mods I like it a lot.
I haven't used the masterbuilt but I assume that it also has its pros and cons.
I have not used a pellet cooker, but I think it has more flexibility - low and slow, higher heat cooking, and grilling.
I know I didn't answer your question in total, but you may get more info on the Bradley forum.