Actually, once you get past the kernel, drivers etc, a fair number of the programs you run under BSD are likely to be the same ones that you run under Linux. So no worries !
I noticed that, I had trouble find a package that wasn't available on both systems.
I did notice that mono hasn't found it's way into the pc-bsd software dir yet.
The only reason I didn't keep it on my machine the last time I installed it was hardware problems.
I (thankfully) have had no hardware issues yet, unlike with Windows that refused to utilise my sound card without the driverdisk.. PC-BSD and Ubuntu, however, both had the sound working out of the box.
Also, this (BSD) is running a heck of a lot fast than than any of my *buntu's and stupidly quicker than my Sled10 install.. All on similar hardware.
I'm hoping that the experience remains this much pleasure.
[EDIT]: I also have yet to find a BSD forum that is as fun and informative as this one. Actually I have yet to find any forum that is as pleasant/fun/informative/stimulating (non-sexually of course) as this one.