I live in a small city (200,000) a half hour drive from the capital. There are no any dealers of industrial sewing equipment in my city, so in this sense it doesn't matter which brand to choose, in any case I will be left alone with my sewing machine after the purchase. In terms of spare parts, the most basic items such as a hooks, needle bars, needle plates, feed dogs and thread tensioners are available for all brands, but there can be problems with electronic components. As for the after-sales service, I'm afraid Ukraine in this regard is very far from the USA))
As for the material feed, I was told that most people choose machines with a top and bottom feed for sewing upholstery, but perhaps this is simply due to their lower cost ). I also heard that machines with unison feed it is not convenient to sew areas with differences in material thickness, because the movable needle can catch the material. I would also like to know the opinion about the power of the motor and the diameter of the pulley. I already know that the standard pulley diameter is 65 mm. But it seems like it needs to be changed by 45 mm so that the sewing speed is lower. I would like to receive more technical details.