Solaris 10 is rock solid. It is more stable than stable can get. I think my Dad has a Solaris rig running from like 4-5 years back that he hasn't shutdown yet. It is pretty old, but he hasn't need to.
The only thing I would see you having a problem with is hardware support. Solaris is like the BSDs, not very good hardware support. That is why you would bebetter off with Linux.
What is the spex of your rig? Maybe you might be able to run after all.