Yeah, but define a hobbyist? Big mills are cheaper (or as cheap) than bench top ones. It's only a matter of setting up and knowing your machine after that. Owning a ground straight edge is essential though.Why not? I did.
A bench top or even a typical turret mill is not going to make a good job of a cylinder head, but anything that spins an 8 inch flycutter with 24 inches of table sliding should be OK.
I suppose it depends how big your workshop is...