For a little more you could get into a Savage. They're just about the most accurate out of the box factory gun on the market. For varmints, accuracy is important. I haven't shot the Mossberg so I can't make a comparison, but I know the accuracy of the Savages.
As for the .17's, to each his own I guess. They shoot a little flatter than the .22's at an increased cost. They also don't have a whole lot of wallop downrange, but that's the price we pay for increased velocity. As for me, I've always went by the theory that if I need more than a .22 LR, it's time to move up to a centerfire. I'm not about to pay centerfire prices for ammo that I can't reload.
I think as a whole, us shooters are turning into a rather lazy lot. Rather than learning marksmanship, ranging, and elevation compensation, we're looking for flatter shooting cartridges.