I recently did a lot of research on the various machines out there and I
have to agree with Richard that the design of the Prusa seems, IMHO, not as
thought out as a number of the newer designs. Not that it's bad - it's just
not as evolved. I'm new to RepRap so bear that in mind when evaluating my
opinion, but I am a Mechinical Engineer who has been designing machines for
7 years now, so I have a fair sense the quality of a design if I look at it
with some thoughtfulness. That's what I did when researching machines for
myself, and in the end there were two that really stuck out to me. Keep in
mind I don't know for sure that I covered all the machines out there in my
searching.

Tantillus:
http://www.tantillus.org/Home.html
http://forums.reprap.org/list.php?279

B9 Creator:
http://b9creator.com/

I was looking for high resolution at a low cost, and I ended up going with
the Tantillus. So far it's just blown me away - much better than the
$30,000 FDM machine I used to have at work, in terms of surface quality and
tolerances. And the support from the designer (Brad aka Sublime) is just
amazing - he is extremely knowledgeable about 3D printing and seems to
truly care about creating a high quality open-source product.  

-Eric