[kev009]

Dollar for dollar, the Chelsio and Mellanox HW is better in terms of features. Better drivers and vendor support at lower purchase price make it a no brainer. I don't know about SolarFlare pricing but it is also better HW.

igb and ixgbe HW seem to be fair, but you can go look at the HW errata to judge for yourself. Intel had to recall the XL710 due to silicon issues. They also had a firmware incident that fundamentally changes the driver interface, so a particular driver will not work between different FW revs.