I own way too many guitar sims, and pretty much standardized on GTR3 and CLA Guitars, especially for smooth high-gain tones. If you want it, I agree with the advice about waiting for a better price for it. I got GTR3 Solo for $18 originally, then upgraded to full GTR3 for $12 when Waves handed out a $30 coupon. Unlike with a lot of devs, their coupons can be applied to upgrades. Unless they've changed that recently. Not bragging about the deal, just saying that, if you're patient, deals do come around.
All that said, I'm having a serious love affair with Blue Cat's new Destructor. IMHO, it's head and shoulders above any other sim I've tried. Put your own compressor and gate in front of it, maybe turn off the post-amp filter in Destructor and add your own cab sims, such as Recabinet, Rosen IRs, and so on. Add a touch of delay, some reverb, and the sound is amazing and alive. You may want to demo it and save your pennies if you're looking to own just one really high-quality sim.
As usual, YMMV, of course.