You're better off buying the H2 model, as it has an onboard NVIDIA chipset rather then the ATI one which is on the A3. The reason for this is that currently, there is no decent support for ATI in linux.
One more thing, the H2 has a DVI out put, taking into consideration that currently, there's no support for audio via HDMI, you are not compromising anything as the video signal delivered thru DVI is identical to the one delivered thru HDMI.
Hope this helps.
Itsik