They're definately more appealing to me than nitro engines.I think if i was to get a large scale i'd get the HPI
http://www.hpibajaforum.com/Bimages/Baja5BLong.wmv It clearly has better traction and more suspension and just moves better.I wouldn't mind one of those.
At the end of the day though those fuel motors weigh 1600g before clutch assembly,pipe and fuel tank so BL/Lipo is the power:weight winner.The weight of them limits what they can do so much.I think the lauterbacher is the nicest race buggy.MCD have a 4wd MT but it's kinda like a house on wheels.
I'd like to see lightweight, supercharged 4-stroke motors,then things will get interesting in terms of the power:weight contest.