Construction: 9/10 - pretty durable.
Portability 10/10 - the most sound per pound you're going to find.
Loudness: 6/10 - not the best amp for maximum punishment.
Reliability: 7/10 - prone to thermal shutdown if you push it too hard.
Tone: 9/10 - sounds good in all ranges.

At 11 pounds, this unit is a HUGE relief for those pesky "2 flights of stairs" load-ins. I do such a haul on a weekly basis, and I count my blessings each & every time.

1 Rack space is a bit misleading, as you should really leave room around the unit (i.e. another space) for heat to dissipate properly. When things get loud, the Stewart gets real hot, so you don't want to ignore this precaution!

The sound is really superb. Lows, mids, highs are all very musical and all "there". In addition to bass duties, I also use the Stewart for a PA speaker with bass, vocals and guitar, and it sounds excellent.

The short protection works (18 months after an ugly incident & still no apparent damage).

There's plenty of power for many bass rigs, but you may want to consider the 1.6 or the 2.1 models, especially for low B strings at high volumes with inefficient speakers (like Acme or Euphonic Audio).

I've used my Stewart heavily for almost 3 years, and am very pleased and impressed.