I'm receiving less search results indeed and I believe it's something to do with Morpheus Ultrapeers not being grouped together like LimeWire ultrapeers were. (there ratio of ultrapeer connections : 0.6 connections is something like 1:1 instead of 2:1)

The latest cvs code tries to cope with it by glueing LimeWire ultrapeers together more closely (not agressively enough if you ask me). I think it would be even more important to make the leaf nodes prefer LimeWire ultrapeers for optimal performance. I've been playing around with preferring LimeWire ultrapeers recently and I believe it might be benificial, - especially if LimeWire will use GGEP pongs (and other new features) which other ultrapeers might not necessarily understand.