Bloody brilliant. Clear optics, good magnification, well built (definitely got some weight to it). Definitely worth the money in my opinion. (however, haven't use a G&P etc. so can't compare, but I do prefer it to the real steal SUSAT)
As Gim said Diemaco C8 SFWs with ACOG, saw 21SAS with them. Diemaco C7 (ie M16A2/A4) for a pathfinder and Brigade patrol group look (could even add a M203). HK53 for Military police close protection look. Or even get a G36C/K for a Doctor Who/Shaun of the dead look.