Most people say that Smartech is crap. However, I have one. There has been one bad experience with getting a part. (It took 7 months). I would say that it probably holds up as well as any car I have (Savage x and Rustler). I do drive the Smartech differently, mostly on-road, but it is a nice vehicle for me. It wasn't too nice to start off with.

I don't know how their stock engines are as mine had a problem on the third or fourth tank due to a faulty servo. The servo held Full Throttle and bent the piston rod, so it wasn't the engine's failure, but the servo's. The engine ran fine until then. I even put a tank of 30% through it and it was a screamer! I would recommend to replace BOTH servos to anyone who gets one of these. I also don't know how Smartech's transmissions are because mine is a single-speed.

I would never say to get a Smartech over an HPI or some other main brrand because of parts availability and quality of servos. For me though, my Smartech was aperfect first nitro because it was cheap so if i had an accident (I did) it wasn't too expensive to fix or replace. So I guess that Smartech's are o.k. RC's if you upgrade a little bit.
Parts availability can ba a pain sometimes, other times, you get your parts within a week so it just depends. You can also take a more mainstream brand's part and try to retro-fit it.