I recently bought one of the 15-40X60 Alaskan Guide Series Cabela's spotting scopes and I'm pleased with it. It's clear, bright, and easy to use.
I would have a bought a Nikon Spotter XL, but I got a much better deal on a slightly used Cabela's scope. The two scopes are so similar, I believe Nikon may manufacture these scopes for Cabela's.
I have an easier time acquiring objects in the straight type spotting scopes than I do with the angled ones. Just my preference.
Would I buy another from Cabela's? Yes, I would.
My two cents, hope this helps you decide on one.