BoxRec

Which would be best for someone wanting to get fitter and tone the flab away?

For me? Deffo kettlebells.

But they hurt like hell.

Look up a Turkish get up.



Then do them.

I will be using kettlebells as part of functional training, but it really depends on what you want.

If it's just to get fitter, circuit training is much better.

It's a deceptive question, because there are huge variations on circuit training and the two aren't mutually exclusive i.e. it's perfectly possible to have a good circuit that incorporates kettlebells.
The latter are great tools - as Dioufy said, the TGU is one of the best overall body exercises you can do, but you have to make sure you maintain good form when using them. Check out www.dragondoor.com as a useful resource in that regard.