Sam, I have both the Kettlegrips (for about 1 year) and just recently purchased one 35# KB from Iron Woody. The grips served us well at the station for doing swings. To us it feels different from swinging a DB.
We had the smaller Kgrip set at 35# and the larger one set at 55#. We don't do cleans or snatches but the 35# KB it is smaller than the Kgrip with the plates loaded on it and feels more sturdy to work with due to the thin side rails on the Kgrip. I think that it would be easier to clean the KB due to it's smaller size. The Kgrip tended to bend a little at the side rails even though we were careful about not dropping them. Also with the smaller Kgrip you have an allen head bolt on each end to tighten, with the larger Kgrip the bolt is only on one side and you constantly need to keep an eye on both to make sure they are not getting loose. Don't get me wrong it is a great product.
If you are going to be changing weights often, the Kgrips are definately the cost effective way to go. If you know what weights you will be using, the KB's may be better. Hope this helps.