well I left because
- namecoin merged mining does not work at all for me although it is said it should work
- slush's score system is poor because when a block is found really quickly many ppl get so little of it because of the scoring system
My eruptor actually gets a pretty good number of shares on quick blocks, but my GPUs don't. Not sure if it has anything to do with it.
Obviously, if some ppl do not get points on quick blocks, some other will do. This is, however, another unpleasant factor that you can hardly affect.