I can't speak to the 131 but I've ridden a few bikes with the 107 Milwaulkee 8 and it's pretty good. Feels a lot more refined and torquey than previous HD's.
I have a couple of friends that have 107s, and your experience matches theirs and many other reviews I am aware of. And of course now the 114 is standard in a lot of models. Harley though is in real trouble with sales continuing to slide and dealerships closing at an alarming rate. A number of shops have brought out bigger displacement engines with better numbers than this 131. Maybe Harley is trying to cash in on this market, I would assume so. Best of luck to them, because I hate to see what is going on. It will shake itself out. I am pretty sure though my next V twin will be an Indian with the Powerplus 108 as plans are now to put this engine in other models after the success with the Challenger.