Got the Seidio Active case in and here are my thoughts:
As far as the case for the phone, it holds it real tight. No creaking, etc like there was with the otter box. Also it is much thinner. I would be more worried if I dropped it in the case although it still offers protection.
The belt clip is a much better design. No problems with it at all. Phone seems to sit nicely in case and does not feel lose.
The only other thing I don't like is that there are no covers for the openings on the phone like the usb, headphone jack. Overall very good product.