I've used the BX2750D 50" for 6 seasons.
Biggest snowfall was 34" in a day. Get a foot + a couple/few times a season.
My driveway is short but wide and all stone. I need to throw snow for distance sometimes.
All-in, my only complaint has been the shoes, but I believe more recent models have a different shoe design. I modified mine to suit. I've had no problems with gauge of steel, construction, etc.
Anything over 6" of heavier stuff gets my BX2360's attention....need to slow down. I can ram through 10" of dry, cold Lake Effect pretty quick.
I wonder if the extra 5" might just be a little more for the tractor to handle, but many guys here have them, and I don't recall it being a problem.
I've never seen an HD model in person, so can't comment. There are places 55" could be a concern (walkways, etc.) for me, but not a big deal.
I am a big fan of HD. Just wanted to toss out that I haven't had issues with the "regular" version, and I've worked it pretty good.