At this point, I still use Delphi alot for my projects because it just feels comfortable. Allthough FPC/Laz have a great featureset, delphi is very stable and does it's job well. I would love to start using FPC/Laz for all my code, but there are a couple of things getting in my way.

> I've found that the delphi debugger works great in 95% of the cases, but GDB let me down way more often. It often gives me errors like: Symbol not found in context or similar. I just tried to debug an application, but it didn't work AT ALL. It just seemed to hang in debug mode after I hit F9... Ctrl+F2 doesn't help, and after some time the application will be shut down automatically (Do note that I am using an automatic build of a few days back). Also, each time I start my application (with certain linker options) i get a SIGSEGV error from the debugger, which is really annoying when you want to test your software quickly. I want to feel comfortable with these things, but I always end up getting annoyed by these issues.
> In delphi, I love to CTRL-click somewhere to jump to the definition. I really miss that in Lazarus.
> On ubuntu, it is not possible to restore the entire IDE with one action. I have to maximize every single IDE window separately, which slows me down quite a lot.
> And a nitpick: The delphi compiler seems quite a bit quicker than FPC. Not a big issue for me though, but it belongs in the list.

I want to start using FPC for the following reasons:

> Cross platform and 64bit support. ofcourse!
> I like how lightweight it is compared to Delphi, yet offering a lot of tools and components.
> I like the FPC pascal dialect (for example the +=, -= operators) and the fact that it's a bit more strict than the delphi syntax here and there.
> And it's opensource!! Would like to contribute someday, when I have a good idea for an extra feature.

I'd love to use FPC/Laz more often, when they are more stable and have a good debugger. That's their main problem now, so I believe. Now, I still use delphi mostly, but I try to keep my code FPC compatible.

Just my $0.02.