For your price range you can't go wrong with the SpectraDrive or SCR-DI. High quality build, high fidelity, usable as a DI or headphone practice. I've had the SCR-DI since it was released and practice almost exclusively through headphones. It has an awesome headphone preamp. I like having the separate aux volume control too. Simple to use and very balanced volume between the scrambler, that you'll either love or hate. I think it does a decent enough job for when you want some grit.
I really wanted to like the spectradrive but found myself fiddling with tone patches and frustrated by the volume differences when you engaged them. I'm a "too many knobs" kind of person so take that for what it's worth. The sound quality is good but it didn't sway me from the ampeg. I had two. Returned the first and sold the second.
The new darkglass pedals look awesome but out of your price range. The bass buddy would be the other to consider but it's expensive too. Personally, for practice I like having the option to click on some grit so the ampeg fits the bill.
Good luck!