These are the main issues with labels, you can judge for yourself how these may impact you:
1) Some adhesives may eat the outer protective layer of some discs. (usually cheaper discs)
2) The label may peel when subjected to heat and high rotational speeds. The effect of this may range from damaging the protective layer on the disc to getting caught in your drive's mechanism. (not good) and shattering the disc.
3) Balancing issues causing vibration, poor disc tracking and such.
4) Reflectivity issues on some discs.
This list goes on a bit, but you get the point. Labels are generally safe in audio players that only spin at 1x speed, as long as they don't get too hot. But in high-speed computer drives the balance problem comes in.
I have lots of old audio burns with labels that are doing fine, but I stopped using labels just to be on the safe side, and I never put them in my 11,000 RPM computer drives.