NMS for Carriers

Hi All, We're kicking off a project to find a new NMS and I thought you guys might have some helpful advice. We're a smallish telco (on an island, infact) so we have a very wide range of kit to monitor, from servers to routers to dslams and all that dirty voice stuff. Which software are you guys using? Any obvious gotchas with the various solutions? We're looking at EMC Smarts first. Anyone got any comments to make on that? Thanks in advance! adam.