I have a set of RP Cmans in both SAE and metric that I used for years. They have worked perfectly fine, except on really badly rusted fittings, which usually get the vice grip treatment and get replaced anyways. A couple years back, I lost my 10-12mm wrench, and couldn't find a replacement at Sears. All I could find were sets of the fully polished ones made in China.
I kept an eye out at yard sales, auctions, CL, and flea markets but couldn't find the wrench I needed to make my set whole again. In the process of looking, I did stumble across a used set of SOs in metric that I ended up buying. The price was reasonable, and they are now my go-to line wrenches. I have to admit, they are nice, and do seem to fit a bit tighter than the Cmans.
Although I have not used the Cman polished Chinese set, I would recommend keeping an eye out for a used SO set. I got my SO metric set for $60.00 (5 like-new wrenches). I have since collected an 8 piece SO SAE set as well. CL is your friend.