Several ways have been proposed and applied to compare Language Workbenches (see a review of the work done). Language Workbench Challenge 2014 continues the tradition of inviting tools to be presented showing their solution to the challenge: implementing the support for the given domain-specific language. Past editions of LWC have followed the same pattern in 2011, 2012 and 2013.
LWC is great because it allows people to see different tools at the same time and see how they support the given case. Unfortunately its format is not completely suitable for comparison. One reason is that not all tools participating have implemented all the tasks. Secondly, effort to implement the solution has not been reported (man-hours, number of persons involved, expertise needed, etc.) and I would expect that that would be of interest to many. For example, in 2011 challenge only one participant and tool actually showed in live how the implementation is done. Third, LWC has focused on building a partial language solution from the scratch as in reality - similarly to software development - most work deals with redeveloping and maintaining the tooling while it is already been used. Fourth, there is hardly ever only one person for both developing and using the language, and I was particularly happy to see that LWC 2014 extends the scope to scalability and collaboration (larger teams, larger models, several language engineers working together). These same issues are at least partly demonstrated in a 9 min video showing how MetaEdit+ approaches collaboration.
Single event or study obviously can't address all the aspects of tool comparison, but LWC is bringing perhaps the largest number of tools to the table. Hopefully there will be many submissions. Visit http://www.languageworkbenches.net/ for the submission guidelines.