I have driven both, but camped in neither. SMB and Tiger are the two motorhomes we have been considering for some time as we save up for the purchase. If it were just me, I'd go SMB. My wife grew up in a house like one on that Clean House
show and gets really claustrophobic. She feels the Tiger gives just enough space for her to stay sane.
The pickup frame on both the CX and Bengal is considerably reinforced to the point that there is virtually no flex. Many people in Tigers will go off pavement onto graded unpaved roads, but only a few go onto rough roads and into real boonies like many SMB owners do. A Tiger cannot handle off road/jeep trail conditions that highly modified SMBs can. The members on the Yahoo Tiger Owner Members Board state that they do not have twisting and flexing problems nor creaking noises. The pickup comes without the rear bed, then Provan cuts off the rear wall of the cab and fuses the cabin to the cab. The cabin is not fiberglass; the frame and covering are both metal.
The Siberian Tiger, which will be released in a few weeks, is built on an F-450 crew cab diesel. The frame is not reinforced and is allowed to flex. The cab and cabin are connected with a bellows passage like the EarthRoamer XV-LT and XV-LTS. The Siberian will have a forward facing above cab queen bed with storage on the sides. It will be the height of a Bengal and 2 feet longer with extra internal storage, external storage, and a dry bath. EarthRoamer is soon to release two new pickpup based models as well: one on a 1 ton and another on a 3/4 ton.
The CX, Bengal, and Siberian Tigers offer more space than an SMB, but they are taller, longer, harder to park, more prone to hitting overhead obstacles, more difficult to maneuver, have less departure angle, and are more limited in the places they can access in comparison with the Ford 4x4 SMB (particularly the regular length bed/penthouse roof model). They are available in regular, extended, and crew cabs; Chevy, Ford, and Dodge Ram manufacturers; gas or diesel; 2wd or factory 4x4 (4x4 SMBs are retrofitted by SMB West).
Here is the link to the Tiger owner's group:
http://autos.groups.yahoo.com/group/tig ... omeowners/
If you have more specific questions, you may post here, PM me, join the Tiger group, or any combination. Good luck.