Some are worse than others, but there is latency across all the new servers. There was a correlation to the number of records in msrepl_commans and performance. But even when we set ImmediateSync to 0 and running the Distribution Cleanup job every 30 mins to keep the table size, this didn't help with I guess suggests it is an issue with applying the commands at the subscriber rather than getting the off the distributor?
There is no latency on the 2000 boxes
It could be.
For clarity, you have 200 publishers (140/60 2000/2008) delivering to a single subscriber using push transactional replication. All of the 60 2008 publishers are experiencing latency at a currently unknown "bottleneck".
Are the subscriptions going to the same database/objects?