Well I was thinking about the same thing
Heres what I found

Buggies are in general, FASTER than MTs
Buggies are MORE EXPENSIVE. A savage would definitely cost you less than a typical good buggy. With a buggy you goyya buy the chassis, motor, and radio separately

MTs are more for bashing while Buggies are for racing/jumping

I dont know which one takes more punishment. I've seen both of em go through hell and come out ok.

All in all I think MTs are "for fun" and buggies are for racing.

I bought a buggy cuz I liked the fact that I can choose what I want. and I had a radio anyway so.

If I had nothing, I think I'd go for a MT. Prolly a Savage at that.

Hope it helps
-ram