I really like the other hsgi great that I have, and the sure grip belt gets good reviews. If like to try one out next time I see one on sale. I'm not sure the hsgi Rogers belt is worth the $$$$ it costs though. Anyone have a good alternative that is, hopefully, less expensive? Will any old riggers-type belt work? What does there $65 hsgi belt do that $30-35 belts don't?

It's the cobra buckle. If you've never tried running the other end of the belt through your belt loops with gear over it then it's hard to explain the awesomeness of being able to just clip it on and you're done. Get the cobra buckle if you don't want to end up spending more money on a cobra buckle belt later.

I see that the Aussies have some competition from raptor buckles note. They cost about $25 too. Outside of the buckle, and the correct belt width, is there anything special about the design?

Not really, there are some nuances with how you can attach a carabiner (hsgi uses a V-ring) for emergency rapelling or mainly for securing yourself if doing airborne stuff (both things that aren't really important for your average joe) but most are the same design a QD buckle (namely the cobra) and 1.75 webbing (or 1.5 if you so desire) that is adjustable. If you need the velcro then they have that option as well.