shooting white steel plate you can do well with 10X ,,but I really like the 8-32X zoom ,,I shoot it a lot on 12-15 power but when shooting at stuff like one pound powder cans or clay birds it is nice to crank on up high as you can and still see through the mirage,,you dont have to use it but it is easier to dial it down than not have it,,
if you already have something in the 4.5-14 or 6.5-20 range you should try using them before buying another,,20X will get you a long dang ways,,,
I was at Rockcastle one day and hit the 1,525 yard plate with a 4.5-14 Leupold on a Savage 338LM,,it made a couple guys there kinda turn their nose up at me,,LOL