Idk how ppl think youre supposed to swing a large pipe cutter under a floor or in walls. This is a job for a grinder and sawzall. If youre worried about sparks lay wet rags all around to catch the worst of it. Use a sawzall to finish the cut if access is limited and you cant plunge the grinder any deeper.
As far as grinders, i prefer the nicer dewalt 4.5” model, I used to have a makita that up until it was stolen was indestrctible. Ive had alot of grinders, where space is a concern corded has a smaller profile than cordless. A guy that I weld with on alot of jobs with is always buying hf grinders. He just doesnt seem to care about having a nice grinder, he just burns one up every other month and just buys another of the same every time. Shop around for clearance display models. you can get a brand name for $40 if you get lucky