I love the Peavey Bandit in all its manifestations (the pic above is its latest design), it's the splendid overdrive- very saturated & heavy. More importantly, it doesn't mud-out.
I thought there was no formidable alternative to the Bandit but until recently (if you deem 2 years ago, recent...) Sound Drive's SG612R did very well to prove just that. I just can't exclude the creamy yet defined overdriven tones on board. Highly recommended.
Randall's Ninja combo is the most affordable on this list (at entry time, it lists for <$250). Let's put aside the Mike Amott influences here (it's his signature amp, anyway...) & hear how good this one is. I just wish the manufacturer would include a reverb option in time to come to make it more expansive, not that it's loathsome as it is. 
The Ibanez TBX range is the revised edition of the manufacturer's TB models. The amplifier has a dual midrange control which is very much its strength in retaining clarity. I would advise you to consider at least the TBX30R if you have your mind set on an Ibanez amplifier, I cant accord positive remarks to the smaller versions simply because of the different overdrive/ distortion tone-to-volume manifestation in use.
Marshall revised their MG series in 2009 (these are now known as the MG4 range). Do they sound much better than their previous incarnations? I'd say they sound more organic, alluding to the manufacturer's tube type voicings rather than being the coarse sounding amplifiers they were known to be. Selected MG models feature minimum on board effects for your tweaking pleasure.The places where you can check the above amplifiers out:
- Peavey/ Ibanez: Swee Lee Co.
- Sound Drive: Standard Value
- Randall/ Marshall: Davis GMC
