i've had an experience owning a redcat, and being the only experienced ex racer from 15 years ago, i worked on 3 other redcats. the quality in parts are really just inferior compared to hpi and traxxas. more importantly hpi, because it seems as though redcats are really just a chinese copy of hpi's. their 1/10th scale is some weird cheap version of the rs4/mt line.
the cheapness in parts adds to things breaking. now, is it worth the extra money to have a more solid piece of metal? depends... but here's just a list of inferior parts that i've come across. the worst pieces are obviously the dogbones, they tend to warp and break repeatedly, even with zero collisions. that is not a part that should just bend the first time using it out of the package, if you haven't hit anything. i had one s30 that kept snapping drive shafts in the rear for no good reason.
drive cups, these just get literally eaten and notched from the dogbones, and if you don't keep replacing them, you will literally burn a ring around the inside and its gone.
2 speed transmission is junk. the clutch is literally a carbon copy of the hpi, only made crappy. the aluminum clutches tend to melt rather quickly too.
shocks, the shocks look pretty nice for what they are, but they are so cheap that they instantly bend the shafts, enlarges the hole, and leaks out your fluid. no way to really fix that, besides constantly replacing them.
the plastics are obviously subsomething quality. they break very easily, and have no bend to them at all. the shockwave is probably the worst design, because they are copying the rs4 onroad car knuckle, which also breaks, and they are extending it out and putting a wheel on it 3x as big, so they tend to break for no reason. i had one shockwave that litearlly ran into my friend's foot and broke both knuckles, at MAYBE 5mph.
the shock towers are so thin that every roll over they bend, stretching and bending the shocks. the wing mount design for the shockwave/s30 really bends these, to the point that it forms stress fractures around them. the chassis, same thing, one impact and you bend the chassis, and they tend to warp not only on the front differential section, but also by the engine, which really affects your gear mesh, which eats your gears, etc. and that's something that a beginner wouldn't even be able to diagnose, so they would maybe readjust the engine, but when the chassis flexes and its warped, it brings the gears in and out, and keeps eating them indefinitely.
the bodies are even terrible, they shatter before they bend. no way to fix them, they just fall apart, and you replace it.
this is just my opinion, but if you take all the parts that need to be upgraded, you would be in price range of a new real hobby grade car. if you looked used, you could even find something far superior for the same price. to prove that theory, i just picked up a traxxas revo 3.3 in new condition, for 175 bucks. that's as much as my vortex cost.
now, because i have experience in this hobby, my vortex is still running fine, but i have replaced parts with their various rs4 counterparts, and i'm probably another 150 bucks into it, including shocks and wheels. it rides OK, but seriously, no matter what i do to it, it will not handle like a slayer pro. and why should it? but if they are going to market something as a shortcourse truck, it shouldn't just be a buggy with different wheels. its just not designed right. its not designed at all actually. its just copied, and turned into something else.
so if you are going to buy a redcat, i almost want to say don't bother upgrading anything because its just a waste of money. 50 bucks for shocks, 65 for wheels, nevermind the replacement parts, and "upgrades", you will be in the price range that you were avoiding quicker than you think. the engines are great, they run, no problems with them... its just everything that they come in contact with that is the problem. redcat really had an opportunity here to do something, but they really just wanted to make a quick buck. i've run the aftershock and that is far superior to the 1/10th scale. so really, if you are going to go redcat, and you really do want to save some money, go 1/8th scale, because the 1/10ths are just really poorly made rs4s.