I own two Canon EOS bodies, a 450D and a 7D. I did quite a bit of research on battery grips for the 450D some time ago, and settles on a Zeikos brand one. I was extremely happy with it. The build quality was superb, the grip rubber was nice and grippy, and very similar to the native grip of the camera body, and it offered all of the features of a Canon brand grip.
I purchased another Zeikos grip for my 7D at the same time I purchased the body. I'm just as happy with the 7D version of the Zeikos grip as I was with the 450D version. I think it may lack one or two of the features of the Canon brand grip, but I don't think they were particularly important to me when I made the decision. All the critical functionality is there, and most importantly, the grip supports two batteries rather than one. Additionally, Zeikos grips always support regular old Duracell, Energizer, Rayovac batteries...AA type for the 450D, 9v for the 7D...and in a pinch, that can be EXTREMEY valuable.
And on top of it all, the Zeikos grips are a small fraction the cost of a Canon brand grip. I would recommend them to anyone who needs a grip and doesn't insist on brand matching. The Zeikos grip for the 60D lists for $90, while the Canon grip for the 60D lists for $270. On Amazon, the Zeikos is currently $61.66, and the Canon is currently $174.88, a difference of almost three times. Functionally, I don't think there is a scrap of functional difference between the two, and the Zeikos is a few ounces lighter.