In my opinion not having flat sides is not a bad thing. With sides like urbanartt, addict, and ethic I feel that the edge gives you something to dig your toes and heels on/around which makes it easier for me to do double whips flat.
Proto baby scs is around the same weight as tilt and phoenix. I have ridden tilt, phoenix, and baby proto scs and in my opinion I can not really see much difference between the three of them.
Really isn't worth anything unless you are selling to a collector, ot you might be able to scrap up a couple bucks from a pawn shop. Really no use for it in the sport of "freestyle" scootering. But, it is a pretty sweet collectors item.
I would not say I am the cleanest rider in the world but I'm not incredibly sketchy. I have been riding grippers strong for 6 months with no sign of dehubbing and no chunks. The only reason i am looking into new wheels is because my protos are getting so worn down.