Issues with computer as a wireless access point

Hello,

I am a newbie to wireless technology, and now choosing wireless devices to
set up my home network. I have some questions, and your help is sincerely
appreciated!

I am going to set up a 802.11a/b/g network with FreeBSD host as an access
point. The host can be an old laptop with PCCard, or desktop with PCI card.
I know that DLink, Netgear and Linksys produce cards on Atheros AR5212
chipset. Since I read many negative opinions about Linksys wireless
products, the choice is between Netgear WAG511 (I found no PCI version) and
DLink DWL-AG650 and DWL-AG520.

My questions are:

1) Which products re believed to be better, Netgear or DLink?

2) If their mix is used, the performance is expected to be worse, or each
particular hardware piece can give different results?

3) I would prefer laptop as an access point (smaller, easier to move), but
unfortunately it is not possible to connect antenna to PCCards (unless
one takes an approach described in
http://www.nodomainname.co.uk/ma401/ma401.htm). I therefore suspect the
performance will be low. Will PCI adapter DWL-AG520 with antenna, used as
access point, give performance comparable to real access point?

4) Atheros "turbo" mode is advertised on Netgear webpages but not even
mentioned on DLink pages. Is not it strange? Could it mean they disabled
it?

5) Is it possible that access point and some of clients work in 802.11g,
and some in 802.11b at the same time? Or all of them must work in the same
mode?

Thanks a lot,
Alex