Thunder tiger offer two good buggies, the EB4 S2 and the EB4 S3 both are good rigs, the EB4 S2 can take a beating and keep going, the EB4 S3 is more of a track rig than the S" tho, and the S3 has the option of (from another unit using the same chassis) of a 2 speed.
I have four EB4 S2's. Three have taken a serious beating (i'm just in the middle of finishing the build of the fourth) and kept going. Apart from the occasional replacement part due to an accident, they have all taken more than what i would call "Normal" abusive handling. The stock engines are strong and they carry some good speed aswell.
There is also of course, the hyper 7, hyper 8 and hyper 9, the XTM buggy, and a few other buggies in 1/8 scale that are good.
As to 1/10, thunder tiger offer thewn tomahawk, which received good reveiws, but i am unsure as to what other 1/10 buggy's are out there.