You may want to check out a couple threads if you are considering purchasing from MGR.

http://www.faunaclassifieds.com/foru...ad.php?t=90850
http://www.faunaclassifieds.com/foru...ad.php?t=97437

The bark and mulch trap heat, so you may want to 'fluff' the bedding periodically to allow the heat through. Also no matter what type of heat source you are using you will need to control the temps with a thermostat.