Yesterday I played Moonsea in the afternoon and evening. There was a bit of lag, but it was very playable, and it was better than Khyber (although the airship portals are still broken). When I finished, I went to do the gold roll on Shadowdale and Thrane. Shadowdale was horrible; the bank was irresponsible, wouldn't open, or took ages to open and accept the stuff I put in. Thrane was a bit better, but it was also slow and the lag was noticeable.
What a difference between the servers, really. The population doesn't seem that different between Moonsea and those two American servers. It would be worth SSG examining what other technical differences there are between them.