We have had our M22 for a little over a year. My favourite feature over the other models is the large slide that is long enough to sleep adults. My least favourite feature is the shower that is perfectly sized, if you are a smurf. It truly is a shower of last resort, but when I consider the big picture, we always camp where there are showers. The TV antenna performs poorly, but I think that is because it is omnidirectional, and aerodynamic. Our unit appears to be well built, with no major quality issues. However, I am reading far too many posts relating to delaminating, and it seems that Heartland couldn't properly put a tv cable connection on the end of a piece of coax if it's life depended on it. Go with the M22 for the large slide and extra space, and keep your eyes open for a convenient shower!!! Best of luck making your decision.
Cam