1) THe 33.3 MBps is probably a more accurate number for the drives actual transfer rate, the 480Mbps is just the USB2.0 spec max transfer rate, the fastest that a USB port can transfer data. 33.3 MBps is more than fast enough, it is faster than 16x DVD (which is 21.1MBps)
2) Compatablility is not an issue anymore. DVD drives have all been out long enough that they all work with everything now. I remember when I bought my first DVD drive Nero was the only program I could get to use it, but now they are all supported and plug and play with the OS without drivers (as long as you are using a newer OS)
3) I don't know about noise and heat, likely not much of an issue given that the drive is small and isn't extremely fast, but coasters shouldn't be a problem, as buffer under-run protection is standard and prevents almost all mis-burns that aren't user error.