I would recommend the following 2, they both have better glass than loopy MK4s, better warranty, better CS, and cheaper. I prefer the Vortex, but the bushnell is a great choice as well.
Vortex Viper PST-FFP 6-24x50
http://www.opticsplanet.com/vortex-viper-pst-6-24x50-ffp-riflescope.html
Burshnell Elite Tactical G2 FFP 6-24x50
http://www.opticsplanet.com/bushnell-elite-tactical-6-24x50mm-rifle-scope.html
If you got money to burn, my scope of choice would be a Nightforce F1 or a Premier Light tactical. I will eventually move up to one of those, but for now. My Vortex Viper PST will do just fine.