I have one with an xw7 eyepiece making it 90 power. I use it for finding deer way up on the mountain and counting horns. It needs a heavy duty tripod to stabilize it. Because of it's size and weight it never goes more than a few feet from the truck. It does what I bought it for and I'm happy with it. Also, at 90 power, mirage is a real issue. Once it warms up a little, it's useless. You could always change to a lower power eyepiece when this happens.
If you are buying it for the power (like I did) I'd also look at the Rogue River Super Scope. Good price relative to the German glass, great optics, and because of the double eyepieces, more comfortable for extended glassing sessions. It's even bigger than the Pentax PF100.
Here's a link:
Rogue River Super Scope... The New Standard for Excellence