Webwork Question type has some serious issues. If you search on this site, you will find a prior post of mine that details the problems. We used it for about a year on our site, but the problems were annoying enough that we moved back to the Webwork Moodle bridge.
I have discussed this with Mike Gage and he says that the Webwork Question type needs a lot of work, but is not on his radar yet.
The Webwork Moodle bridge has issues of its own, but they are minor compared to the problems with Question Type. I have moved my courses over to the bridge and am much happier.
Of course, if you are happy with the use of question type, go for it :-) Webwork question type just hasn't been that good of an experience with us.
As to your question, we suceeded with the installation, but it required a lot of fiddling, and we inserted some custom code to get some things working the way we wanted. (I don't know what the fiddling was, and don't know if my computer support person still has the code).