which scope
If you haven't got the $3000+ for the real deal, some cheapo spotting scopes are better than others.
The boys at Nanaimo's Wholesale Sports let me take a top-quality Swarovski outside at dusk one night, and compare it to a couple of their cheapo models.
The Swaro was the classic reference - crystal clear, bright like daytime (even well after sunset), and the depth of field was amazing.
The winner of the cheapos was the Vortex Nomad, which had (as far as I could tell) the same level of brightness at 40x (both were 20-60x60 scopes, I think), the Vortex was pretty clear, but not as good as the Swaro (of course), and its depth of field sucked compared to the Swaro. But it was $375, not $3000+. If/when I can afford a "good" spotter, I'll upgrade. In the mean time, I spend more time focussing and don't worry about abusing it.
I really wanted to like the Leupold 15-45x50 compact (I think anything more than 40x is un-usablel on a 60mm objective, and 80mm is too much to pack around), but it wasn't in the same league as the Vortex, even at nearly twice the price.
Just my 2 cents...but I highly recommend "try before you buy"; get in there on a slow night and just around dark and you'll get a sense of what these things can do...