I'm trying out EclipseFP 2.5.1. I let Eclipse update the plugin, did a restart, then let EclipseFP install all Haskell libs. Then the syntax coloring (and tooltips etc.) wasn't working, so I restarted Eclipse. Then syntax coloring worked and it asked to download the Hoogle DB which I confirmed. While doing that, I opened a file, typed "fo", pressed ctrl+space and then Eclipse just hang. I waited 3 minutes and then it continued. I don't know if this was because of the hoogle download, but in any case it shouldn't happen.
OK, code has been improved to not block when the hoogle database is being downloaded.