Weight weenies (many of ourselves included) have long been fans of foam grips because, well, they're light. However, the downside to lightweight foam is that it's hard to remove them without damage to the foam, and the same folks who always look for the lightest weight are the ones who keep changing components on their bikes, and therefore are the ones always slipping their grips on and off to accommodate other component transfers.The good news is that foam grips are relatively inexpensive and if you have to replace them every time you stick on a new bar, shifters, or brake levers it's not the end of the world, but the even better news is that Cannondale now makes high quality foam grips that lock in place (and therefore unlock "out of" place). While there's a slight weight penalty compared with traditional foamies the advantage of being able to easily slip the grips on and off may be a good compromise.
As for feel, these grips are much the same as other foam grips on the market, in terms of both diameter and density. One other little cool thing to note though: These grips have built in, very light weight bar end caps - a nice little touch.
For just $22 a pair these grips may be the cheapest dollar to gram weight savings upgrade a weight weenie can make.