<p>What do you think of <a href="http://quagga.net" rel="nofollow noreferrer">Quagga</a> compared to XORP as a dynamic software routing engine? What are the technical merits of each engine comparatively? Additionally, what do most people think of them from a programming view. Who has manipulated networks using these enginers? I was wondering from an OSPF, routing, BGP protocol user's perpspective. </p>

What do you think of Quagga compared to XORP as a dynamic software routing engine?
It is one of many options, but not particularly of very much use to you based upon your questions/information that you posted here. Have you tried looking into some of the alternatives such as (nothing comes to  mind)?
What are the technical merits of each engine comparatively?
Small, fast, oddly placed, optimized, super-heroic and more filler for a resume.
Additionally, what do most people think of them from a programming view.
I can't speak for most people, but I for myself do not give it much credit or merit, or well... you know what I mean.
Who has manipulated networks using these enginers?
I could not find specific references, but I do remember reading that both Disney and the 'famous' YUV corporation of South Africa both played with this notion before. I believe Disney abandoned it with the fall of Michael Eisner.
I was wondering from an OSPF, routing, BGP protocol user's perpspective.
I am a BGP protocol user's prospective. Hopefully we hear from OSPF and routing user's perspectives shortly.
Good question.