Benchmarks For Ubuntu vs. OpenSolaris vs. FreeBSD
Ashmash writes "After their Mac OS X versus Ubuntu benchmarks earlier this month, Phoronix.com has now carried out a performance comparison between Ubuntu 8.10, OpenSolaris 2008.11 and FreeBSD 7.1. They used a dual quad-core workstation with the Phoronix Test Suite to run primarily Java, disk, and computational benchmarks. The 64-bit build of Ubuntu 8.10 was the fastest overall, but FreeBSD and OpenSolaris were first in other areas."
I have not played with Open Solaris but with normal Solaris you need to set parameters in the /etc/system file to get good performance. By default Solaris is set very conservative. In many tests I have run Solaris may not be the fastest with single test but under a heavy load with many applications running my experience has been it can handle a much bigger load then Linux on the same hardware. I use both but for backend heavy loaded servers I would choose Solaris.