Well, I think that you should decide whether you want a variable or a fixed power first. Both are good scopes, but it's apple to oranges, really. If you aren't going to hunt with it or take close range type quick shots, then the fixed power would be fine. If you're going to use it to hunt, having the low power available for a good field of view up close will be an advantage...for long shots, you usually have the time to get set and put the scope on the higher range.
If you want a fixed power, you aren't going to beat the value of the Bushnell. You definitely get the most bang for your buck in a tactical scope with it.
The Meuller line has gotten great reviews on GB and other websites. This scope was specifically reviewed on Sniper Central. I haven't used one, but if it was in my price range, I wouldn't hesitate to get one.
Keep in mind that 99% of variable power mil-dot scopes are designed to mil only on a certain power, usually the highest power in a low power scope and between 10x-14X on a higher power scope. To use the dots for accurate range and windage estimation as well as holdover (if you don't click elevation), you'll have to shoot at the specified power.