Pluses: Simple systems and airframe design, Reliability, good load carrier, rugged, great single engine performance, great strip performance both landing and takeoff.
Minuses: 155kt cruise, noisy but not as bad as a skyvan.
I have operated the Twin Otter, Skyvan, DO228 and the Nomad. They all have their pluses and minuses but the Twin Otter is definitely the best all rounder.
Basic wt in the 5600 lb to 6000 lb according to options. TOW 12500lb. Burns 600lb/hr @ sea level, 550lb/hr at 5000ft and 505 lb/hr at 10000ft.
The -300 will maintain over 10,000ft on one engine at ISA +15
I have flown the aircraft in ferry configurations at 18,500lb and it still goes OK