It's working fine for me. Installed this morning and haven't had any problems. It seems to make MBA run slightly faster. I do know startup is faster by a few seconds. The install is very easy. Just make sure you run the Snow Leopard update to make sure you have the latest version before you download Lion.
Been using it for a couple weeks and it feels the same as Snow Leopard other than a few UI changes, I do believe it has a marginally larger memory footprint. Disk encryption is substantially improved.