I have several times asked for a professional qualty study of our different laguage versions, but not seen it exist or being done.
To ?provoke? I therefor list here my subjective impression after daily looking into the different version for 5-15 articles (new ones being created on sv.wp) (I list them in order how often I use them to calibrate the svwp articles).
enwp- a magnitude better then any other. main weakeness are articles on marginal subjects that seems to be allowed to exist there, even if rather bad, and without templates (noone cares to patrol these?)
eswp - a very good version, which in the general discussion are not getting appropriate credit
dewp - good when the articles exist, but many serious holes. Is the elitist way of running it, discouraging new editors in non obvious subjects (that after time passes gets very relevant)? frwp - also good, but somewhat scattered quality both in coverage and the different articles (even in same subject area) nlwp - very good coverage in the geographic subjects, decent quality on articles but limited "world" coverage in areas like biographies itwp - good articles but a bit italiancentered,
nowp - small but decent articles. Their short focused articletext sometimes give more easyaccessed knowledge then an overly long one in other languages
ptwp - the real disappointment. it is among the top ten in volume and accesses but clearly missing a lot, and even existing articles are uneven. I now use it even less then Ukrainian and Russian which I use very seldom as the different alphabet makes it hard to understand the article content
(arabic, chinese and japanese I almost never use, too complicated)
(I also use some smaller ones like sqwp and mgwp (hungarian), in these versions I have seen serious quality problems not to be found in any of the above ones, I am not sure they even have basic patrolling in place)
Anders