I was on middlecoin from the start up until Max came out and I never had rejects over 5%. I assume that is because the newer more profitable low diff coins couldn't handle the volume of MC so we didn't have the low diff reject issue.
What I am concerned with is comparing apples to oranges - reject rate needs to be taken into account when comparing profitability.
I do wish Terk would take down that announcement that the Rejects issue is resolved. It clearly is not! Pool rejects continue to bounce around way over the normal 2-3%. I've had (brief but seemingly valid) periods of almost 0 rejects, but 10-15% is typical and in the last 10 minutes I'm running over 31% rejects! I've tweaked and tweaked settings to no avail, it is jumping around due to something on the server end. It's making me pine for Middlecoin, which is ridiculous...
5-15% is typical. Depends on what coin is being mined. Avg on middle is 7-10%, again depending on what coin is being mined.