I prefer cutoff wheel on a 4.5" electric grinder. With a 5 o 6'' wheel. more power than a cheap air grinder, and control. An air equivilant would be a $300. grinder. And Bosch is the only grinder I`ll buy now. But all will have its place and uses. sawzall, etc. Never used a nibber, but they seem to work well, one advantage would be no burr. you get a big one with a cutoff wheel. If you have the resources, get em all, they`ll all come in handy. and a Plasma torch is sweet for fast roughing, and getting in tight places. But if I could only afford one tool, it would be the electric 4.5 grinder. multipurpose tool man. grinder,sander,flapdisc,flapwheel,cutoff!!!!! oh yea, and cupbrush and wirewheel. 7 function tool:-D Damn, you guys type fast!lol