Given your clearing area and location with lots of snow the YM could be a consideration just on the 24 versus 20 inch clearing width.
For some people storing their machine in a garage the 20 versus 24 becomes a consideration when storing it beside or between cars or in front of cars. The small footprint can make a difference.
The Ariens will have a bit more robust body but not to the extent of their reputation which comes from their larger high end machines. The MTD is not a bad machine and could last 15 years if you use it properly, store it properly, do the maintenance, and clean off the machine well after use.
The Ariens engine is a standard Tecumseh very good proven L-head engine. MTD is now using a foreign made Chinese engine. Getting any detail on these engines has been difficult but I would guess MTD has selected a reliable design and overseas maker. Both have a lot to loose if that is not the case. Their OHV is not a super new design introducing exotic features like a Japanese car engine. It’s a pretty basic OHV, probably well made, and a safe bet.
If your a first time buyer there is some info at: http://www.kedawei.com/snowblower.htm
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