We had a 1790 with significant in-row pacing issues.   I had heard the complaints before we owned it, but really didn't give them much credence, but after having issues and having run a 7200 with similar meters and excellent results, the only thing we could really point to was the pro-drive.

We solved the problem by trading for a couple 1200 series CIH.  

I don't really remember ever having any sort of problem with chains.