For the price, this might be the best Marshall tube head you can get.
The amp is pretty much a jack of all trades, yet absolute master of none. The presence and resonance controls really help out getting many different yet Marshall like sounds out of the amp. The controls seem quite active, so little adjustment can make a big difference.
DSL20HR really excels in 70s and 80s rock sounds, and has more gain on tap anyone will probably ever need. For the real chug, you will still need an overdrive pedal to tighten the amp sound.
For the technically inclined, the 10W/20W of dual EL34s is achieved with lower plate voltages. The power amp is also cathode biased, so power tubes can be switched without needing a rebias.