See my recent posts on assessing optical performance at the SHOT Show.
http://www.longrangehunting.com/forums/f18/hawke-sidewinder-vs-vortex-viper-vs-falcon-menace-84839/
I can only comment on what I evaluated. I reserve the right to edit these lists after reviewing my notes from prior SHOT Shows. My list of medium mag scopes with good optical performance for their price points include:
Burris FF II and XTR, Bushnell 6500 and some Tactical models (3-12x44), Hawke Sidewinder and TAC, Leupold Mark 4, VX-3L and VX-6, Nightforce, Steiner, Zeiss Conquest and Vortex Razor.
At the high end, Swarovski, S&B, Zeiss and Kahles all have great optical performance.
I'm not favorably impressed with Meopta, Minox, Nikko Sterling, Nikon MXXX, P223 and Monarch, Pentax, Shepherd, Sightron SII and SIII, Vortex Viper PST & HS. The optical performance is average, at best, for their price points.
With the exception of Hawke, I haven't found any Chinese made scopes with acceptable optical performance and quality.
I don't see the need to buy a scope with average or marginal optical quality. There are plenty of good optical quality scopes out there. Pick one with the features you want and that you can afford.
When it comes to magnification, less is more. Veiling glare is a key discriminator in scope optical performance. Higher magnification scopes have higher glare, and also require larger objectives for the same brightness. The larger the objective, the more glare. Buy only as much magnification as you really need, and no more.