Just my 2 cents.

I'am using cgminer 3.7.3 (kalroth cgminer 3.7.2) no problems und running smooth with us.clevermining.com
Just peaks of rejects and stales (round about 4%-8%) ---> for me  problems with miner settings (queue/expiry/scan-time)

I can manage my miners with cgremote and the rejects and stales are identical in cgremote, at the miner-console
and at server side !

Today i switched to eu.clevermining.com:

1. The rejects at the server are going to 0% but
2. the console and my cgremote are showing from 75% to 85% rejects.

I changed only one thing in the configuration: i put in an extra fail-over-server (us.clevermining.com) at the second place.
(there are more than one fail-over-server in the config)

Just wonderful, no stales and rejects at server-side but a lot at my side.
i think these are not really rejects and are results from:

Rejected untracked stratum share from pool 0

This situation is not usable for me, because i a can not differ 'real' and 'fake' rejects.

So i downloaded sgminer 4.1.0 cut of 2 lines out of cgminer.conf renamed it to sgminer.conf and start.....

WoW

No/few rejects at server side and same amount at my side (at the console and cgremote)
and at least and the very best 1-5% more  WU: (after 2h)

Have a nice evening and

@Terk ...........many thanks for the eu-server and your fabulous work ! *chapeau*