Is RAM from http://macramdirect.com good?

They are guaranteeing compatibility and have a lifetime warranty, that's good.

They also claim that they sell Samsung Apple Factory Original RAM (as an extra cost option), that just is not correct. Apple does not use Samsung RAM in their G5's exclusively, nor even primarily. Apple uses Hynix, Micron, IBM, Elpida and some Samsung depending on which month it is. It is a sure bet that they are not selling RAM purchased from Apple.

Google is your friend: all of the below information is publicly searchable:

The Web domain was registered in 2001, which is good (there's some history)
William Gonzalez
Ram Direct
910 Jolly Rd
Okemos, Michigan 48864
517 347 7859

This is the phone number and address of

Okemos Design (home builders)
910 Jolly Road
Okemos, MI 48864
(517) 347-7859

William Gonzalez registered two other businesses at 900 Jolly Road in 2002: SCOOTERPUP
TECHNOWIZ.BIZ

You can inquire with the Better Business Bureau whether they are members, and if there are any outstanding issues.
http://search.detroit.bbb.org/nis/newsearch1.asp

There are 2 endorsements I found: at iTweaks http://www.itweaks.com/article.php?story=20050322115617492&query=Mac+RAM+Direct
and MacFixIt
http://www.macfixitforums.com/php/showthreaded.php?&Board=OfficeX&Number=626697
and one problem at MacWorld Forums
http://www.macworld.com/forums/ubbt...=211882&page=7&view=collapsed&sb=5&o=&fpart=1