Since they're a Rails company (althouth this may change given they've hired 2 guys from the Groovy/Grails community ;-) this isn't really surprising. The conclusions are that Rails' architecture is better because:
- Ruby is a better language than Groovy.
- Spring does most of its heavy lifting in the stable layer, which is not the right place.
Stu's, second point is somewhat confusing and contradictory. He link's off to this post by Ola Bini where Ola says and I quote:
"The first layer is what I called the stable layer. It's not a very large part of the application in terms of functionality. But it's the part that everything else builds on top off, and is as such a very important part of it. This layer is the layer where static type safety will really help. Currently, Java is really the only choice for this layer. More about that later, though."
Later Ola goes on to say that Java is no good for the stable layer either and that another statically typed language like Scala would be better, but at no point does he say that a dynamically typed language is good for the stable layer.
Since Rails is 100% Ruby and, according to Ola Bini (JRuby committer) its not a good idea to build "the stable layer" in a dynamically typed language (Ruby) who has the better architecture?
Grails where the stable layer is built on powerful, stable and performant Spring or Rails where the stable layer is in Ruby, which is dog slow and problematic. I'll let you decide.
Personally, I don't buy into Ola's problems with Java for this so called stable layer nor do I believe that a dynamic language can't be used, at least in part, in the stable layer, because 25% of Grails' "stable" layer is written in Groovy. However, what I will say is Relevances' 2 conclusions are complete nonsense and fall into the "Crap" category of their original post.
What I advise anyone trying to make this decisions is download and try out both frameworks and use what suits you and your company. Every business is unique and not every framework is suitable for every business need. Don't buy into nonsense from either Stu or I that ones architecture is better than the other without comparing how it fits into your own existing architecture.