I don't have any stats, but I can explain the basics to you.
Every disk-based system has moving parts and is subject to breaking and "disk read errors" (DREs).
A DVD player that reads both CDs and DVDs is usually supposed to have two lasers inside of it, because DVD and CD operate on different wavelengths. In order to make the PS2 backwards-compatible, Sony had to make the PS2 able to read CDs. But instead of doing it the typical way and including a second laser, Sony made a cheaper "dual wavelength" laser that could "shift" between the two modes. It's apparently a cheap piece of crap that's prone to breaking. If it breaks, you'll either lose your abilitly to read CDs (which doesn't just affect the backwards compatibility, because some smaller PS2-native games have been on CD) or DVDs, or both.
Sony made a newer version of the PS2 called a "50,000-series" which has a quieter fan and a quieter motor. They might have improved the durability of the laser for this model.
But then, Sony made the new smaller-model PS2 which people are calling a "PStwo", and most people suspect that it's extremely flimsy all-around, as the redesigned PSone was, even if some key parts like the laser might not be.
For the XBox, the thing to understand is that there are three seperate DVD drives being made for it by three different companies, called the
Phillips, Thompson, and Samsung. Each model has it's own seperate quality debates, but generally they're all supposed to be better than the PS2.
The GameCube's drive is... ummm... good?