I wired my entire shop with GFCI, because the code says so. Anything with an outlet requires it. The loophole is for hard-wired connections that go to a shutoff switch or breaker. They are exempt because the purpose of GFCI is to protect a person from being electrocuted for touching ground and a live wire at the same time. The assumption is that this occurs at the outlet, usually in a bathroom, with wet hands and some handheld appliance like a curling iron. Pop goes the GFCI.
I have not had a single issue with GFCI in the shop. I have a few GFCI breakers powering 220v circuits to my RPC, a 5hp Baldor compressor motor, my Mig, Tig, and plasma, and my (ahem!) imported tools and appliances that run on EU 240v. All of the 110v circuits have GFCI outlets first in the chain, so all outlets are protected. All of my stuff works just fine.
The only reason I can think GFCI would cause problems is if one did not have an up-to-date or quality tool. It's also possibe that the black and white wires are switched... Bottom line is that ground should never carry current for any reason, at any time except for a fault condition, in which case it should trip immediately.
