Funny. It has been exactly the opposite for us.
We're running a bunch of xfires (14 boxes total, 4100, 4200, 4150) here
and initially started out with solaris because the wise guys said it's faster,
more stable, oh and no least you get that shiny "platinum support" badge...
Yea it was all that and the zfs hype, what could possibly go wrong?
Nothing much to be honest. We fell in love with the hardware immediately
and the machines hummed along without too much trouble. Postgres performs
well, java performs well, and ZFS snapshots are a blessing.
Despite all that superficial happyness we switched most of the hosts to linux
(and aim for 100% linux) after a few months. We still love ZFS (and can't wait
for a linux equivalent) but that alone couldn't justify sticking to solaris for us.
What broke it for us is the userland with all its subtle differences
to linux, or in other words: the learning curve. This may sound strange when
talking about a UNIX OS but as a linux shop we're spoiled by the GNU toolchain,
by dead-simple package management and all the little everyday things that just
work a tiny little bit different under solaris.
I'm not saying the linux-UI is better (actually, it is in many
places, but that's not the point here), it's just that we all grew
up with linux, so the solaris CLI "felt like a really old version of linux"
(to paraphrase a coworker) from the start.
