I would agree with Larry on all points. Sounds information based on my experience as well.
As for plugging it in...
With large temp and humi swings in the ambient air you are likely to get condensation in the unit. Many people deal with this ok. There is a lot on the forums about this sort of thing... here is one good post to check out:
http://www.cigarasylum.com/vb/showth...t=condensation
The all cedar chasen drawers will definitely help with the humidity stabilization. I estimate 400-500 cigar capacity for these things based on my experience.