Wongerboyo: I’ve seen an increase in write quality, as some discs that used to write badly now work fine (The Vanguards that I mentioned earlier, but probably more discs will work fine now.).
Some people say that the drive seems to become more conservative on some media but I’ve mostly not encountered this problem. Every media burns at the same speed or even faster than they did before, and even a burn on the same speed is faster. (32x was 3:57, now 3:20, for example.)
The only media that I’ve seen the overclocked one burn slower than the 32x one was on 16x TDK/Ritek media, that used to burn at 32x but with the overclock burns at 24x, but when burned at 32x the media got quite some C2 errors near the end, and at 24x it is fine.
It is a drive to stick to good media, though, but good is not always expensive, as Prodisc and Princo, for example, tend to be quite on the cheaper side of things, even if they’ve never gone bad on me and I never get a bad disc on a spindle.