"Step up" to a burris? I must admit, I found that kinda funny. I own two Burris black diamonds and, while I haven't had any problems (other than it seems that the lenses scratch fairly easy), I have an Elite 3200 mounted on my .375H&H - which has far more recoil than a little .300WSM, and my Elite 3200 has held up perfectly. I just don't see the burris as a step up from an Elite 3200.
That said, on my particular .300WSM (which is a Kimber Montana), I mounted the new Leupold VX-III in 3.5x-10x-40mm. I choice this scope because, in part, I wanted really long eye relief. The new VX-III series is noticeably better (optically speaking) than the older Vari-X IIIs. Also, after about 30 or 40 shots, the scope performed flawlessly. As such, I recommend the VX-IIIs.
Zachary