MTD is built to be at an appealing price point to the average homeowner. Not the highest quality but very serviceable for average (ie: non-commercial) use.
The plus side is that parts are readily available online or from a knowledgeable small engine shop. Also parts may be found at good machine shops if they have personnel that can match up parts by looking at them and measuring.
Just my observations from having worked in the small engine industry for a while.
MTD is a price point manufacturer/distributor that sells a lot through outlets like Lowes. They are a mid-low quality product, for the most part. Parts and service should be no problem. I had three of their mowers and not one survives today. I can't say that it was their fault. They were used and abused plenty. I doubt many other mowers would have survived either. The price was the main reason for me purchasing them. They were bought to be a "disposable" and they served that purpose as expected.