The stitch quality from machines can be affected by so many things that it is not comparing apples to apples unless that person used the same thread in top and bottom, same stabilizer, fabric, and most of all design..in both machines. I have used many different brands of embroidery machines and they all have their pros and cons, but the one thing that is consistent is that they all have sewn out nice designs when given the proper tension, thread, stabilizer, etc.
I know you weren't asking, but if I had a choice, I would always have a machine that I use solely for embroidery. Embroidery can be very time consuming, and I like to have a machine that I can sew on while the embroidery is stitching out..I can't stand to just wait for a design ..I get a lot of piecing done while embroidering..just a personal choice.