I have a 6 year old Kinesis Freestyle (original) that I love. It is the best keyboard I've ever owned, and I've tried many. I have a nice-ish Microsoft ergo style thing at home, but the keys are just yuck compared to the Kinesis. I do technical support, so I type quite a lot and don't need a numeric keypad. Other keyboards made my hands hurt. This one has not. It's logged several hours of WolfET. I like it's smaller footprint. It also fits on my keyboard tray leaving me room for a nice old Logitech G5 on a Razer eXactMat to my right, and a Clearly Superior Technologies trackball to my left (all on my up-n-down GeekDesk - I have name-dropped enough ergonomic brands, yet? I mention them all as someone who has battled the ergo demon for many years and this setup has helped recover my hands and back).
I tried the Alphagrips iGrip once - I can't recommend it.