First you should figure out if your laptop provides two or three antenna (connections). If your laptop provides three antenna connections, you should (but must not) use all antennas for better signal quality.
My laptop provides three antennas, so I have been been using the Intel 5300 wifi card for a few months with 12.04 ubuntu precise now. So far, I did not have any problems or performance issues. To get a better overview, you can find official technical documentation on the Intel support pages.
Be aware! There is a difference between the 5300 and 5100 Model. While the 5300 provides connections for three antennas, the 5100 only provides connections for two antennas. As far as I know, both cards are available in half and full size mini PCI-E.
According to my experience, another big advantage with this Intel wifi cards is the great linux support, so these normally work perfectly out of the box. I hope I could help.