A couple of guys at my shooting club have bought them - very good value for money. They have the 4-20 variety.
Glass is quite close to the S3 as far as I could see without having them side to side - not quite as good but a lot better than say, a Hawke Sidewinder, especially at higher mag.
Apparently the adjustments are not quite as reliable as the S3, particularly at the extremes of adjustment range, but most of us wouldn't push any scope to the edge regardless of price point. The popularity of adjustable rings is testament to airgunners learning that lesson a while ago ?
All in all very good scopes and a good match for a higher end rifle