It's the perfect balance of strength, weight, and design. It isn't unwieldy yet is is thick enough to bring on the heat, safely. Use full, unsplit, hardwood logs, and you will get the longest burn time. Use engineered logs from sawdust and expect 5 hour burn times when the flue and draft are properly set.
As with all stoves, experience is required. Practice out in the open before you plan to sleep with one. Read up on skills needed to properly work a wood stove and you'll be set.
Negative reviews are most certainly from amateurs or people that don't understand design, strength, and weight balance.
Tim 
