I think the Delphi compiler has a few things I would miss in FPC. But most of those are the new additions like class variables and all the OOP goodness

On the RTL side I think FPC is still a bit more clunky and heavy to work with. On several occasions I've managed to crash the compiler when working with some exotic libraries and stuff. (This is a while back so I don't know if the problem persists and didn't know where to report such bugs)

The FPC community also seems a little hidden and/or old-fashioned. Is there actually a specific Freepascal community?