My Comp series has never suffered in temperature. I have had it over 12 months now, so have used it most conditions. It's rangefinding capabilities are second to none, and I have owned or tried most FT scopes out there.
If you wanted to, you could rangefind upto 45 or even 50 yards in 1 yard increments.

I did struggle a little bit with the mag at first, but now I am used to it, I wouldn't swap it for the world.

I had a Leupold 20-50x50 and that was ok until the temperature dropped to around 5 degrees or less, then it would under range by about 3-5yds. But as Ken (Luddite) said, user input is needed with these scopes, and if you know it's going to happen, you can compensate for it.

I would recommend a Competition series Leupold to anyone, and now that the interest rate is so good, now is the time to buy. Neil.