@nickchun said:
Twilight and Thea were developed from Kerkythea (which is free, but takes longer to learn) Materials from Kerkythea can be used in Twilight, so you can develop your own materials in Kerkythea and use them in Twilight. Twilight is well worth the money but if you are really strapped for cash try Kerkythea first.
Twilight uses the render engine from Kerkythea, but Thea render has different core and material system (even the developer is same as with Kerkythea). Thea can import Kerkythea scenes, but it does a one way conversion.
About twilight renderfarm, there is one beta (that actually is Thea based and uses Kerkythea to Thea conversion) at http://renderact.com/. Possible other Thea render farms may accept Kerkythea XML scenes
http://www.thearender.com/cms/index.php/resources/render-farms.html