I've had luck with UTG, Hawke and Sightron scopes. I have two sightrons - an SII 6-24x42 (a mid - level model) and a 4-12 SIFT that is their entry level springer scope (about $200). It's on my .20 Beeman R10 with no problems.
I've had a lot of luck with my Hawke's - an airmax 8-32 and a Panorama 4-12. The 8-32 has been on my 97 with no problems.
The UTG"s are my go to springer scopes. Great warranty, great price, really tough, decent glass. I've only had 1 die on me - it was on a Hatsan 125 Sniper with the NPSS conversion from PA (shot 10.5's at 995 FPS). It took 3,500 shots to kill it and UTG replaced it with no questions asked. I have an 8-32 with the glass mil-dot on the way. I like the UTG"s quite a bit.
There's a lot of options out there like the Weaver V16 and Leupold's that were previously mentioned. You really can't go wrong with any of them - Hawke, UTG, Sightron, Weaver, Clearidge, etc. - you just need to find one that has the features you want and fits your budget.
Good luck - Nico