The are 2 x HRU216's the old HRU216D and the new HRU216M2
The HRU216M2 is a superior machine, thicker deck and different shape compared to the old HRU216D's
The HRU216M2 does it all great with a couple of simple mods like upping the revs and thinner catcher bags.
The HRX217HYU has a bar blade it will never catch as well as 4 high-lift swing back blades
Don't be concerned about the weight if you man handling the mower your doing it wrong, they are self propelled and not for pushing or pulling. I never push or pull the mower.