I have a mixture of all types of clamps, from g-clamps to f-clamps to carver clamps. The ones I use most are the f-clamps, they cover a larger range of clamping and change sizes quicker. There's nothing worse than having to spend 5 minutes winding out a 10" g-clamp. For really serious clamping force the carver clamps are the daddy but are not cheap.
Most of my f-clamps are got in lidl & are decent quality & relatively cheap. They are in store regularly & I buy one or 2 each time.
I've always found that you either get cheap clamps that aren't great, or very expensive clamps that are very good, like Bessey/Carver.
Piher Maxipress clamps are the best value ones I've came across. They have loads of power and are really well made, and price wise slot right in the middle.