At the end the pool fee has more influence on your income than the hashrates, unless you notice a big difference between pools.
Pools showing higher delays have a higher posibility, that the shares you submit are outdated, but I didn’t see any influence for my miner (yes I’ve only one rig running).
If you are really keen on this, use a pool with low delay and best network response time fro your riggs.
Also, if you are not mining 24x7 with one pool, a pool with pps payment scheme is better for you.