Like the H61/H67/P67 motherboards tested thus far, the ASRock Z68 Pro3 motherboard worked under Ubuntu 11.04 in a relatively "out of the box" experience, sans the integrated graphics. The Sandy Bridge graphics support on Ubuntu 11.04 is troubling due to outdated components, which can lead to stability issues and other problems depending upon the workload and system configuration. Additionally, for this Z68 motherboard when initially booting Ubuntu 11.04 the display would be lit up but then go blank.
What ASRock has done with the H61M/U3S3 is created a low-cost, reputable motherboard built around Intel's H61 chipset. The only Linux issues with this motherboard appear to be the lack of LM_Sensors support for its onboard sensors and the SNB Linux driver needing to be updated, but that is not a problem specific at all to only this product. The cost of this motherboard at retailers such as Amazon.com is $75 USD at the time of publishing. This is one of the most affordable Intel Sandy Bridge motherboards we have found to date, and it works well, so if you were on a very constrained budget but looking to have a Sandy Bridge system, the ASRock H61M/U3S3 would be worth considering