I have a Ryobi table saw (don't buy Ryobi). It has these cheap crap plastic teeth in the "rack" for the angle changing pinion. If you leave the angle lock on, and try to adjust the angle, then you will shred the rack teeth with very little effort. In fact, you're likely to shred the teeth even with the lock off... they're pretty much worthless.
Similarly, the mechanism that raises and lowers the blade is dependent on the same junk plastic. I took the cover off of it, and little shavings of plastic fell out of the cup.
In my semi-professional assessment, $.05 worth of metal could have made my $100 table saw a lot more durable and long-lived. But hey, $.05 is $.05.