I don't know about the Sparrow, but I have the Eversewn Hero, and I love almost everything about it. You mentioned the thread cutter and the threader, which are two of the things I'm not crazy about.
Even though the thread cutter is basically in the same position as it was on my old machine, I find it a bit awkward to use. I think it is because my old machine was a bit more rounded and the Eversewn is more square. I usually end up using my thread snips. As for the threader, it works great most of the time, but I just cannot get it to work with larger needles, such as the size 14 needles I use for sewing on denim. It works fine with the 11s and 12s I use for quilting.
The only other thing I'm about my Hero,and I'm not sure if it is a feature on the Sparrow, is the thread sensors. Once the machine decides your bobbin is empty, it will not continue stitching. Its pretty annoying to have to manually advance the last inch of a seam one stitch at a time when I know there is at least another yard of thread left on the bobbin. I also learned to ease things like sleeves by stitching without thread, and I just cannot do that with the Eversewn.
Otherwise, I absolutely love my machine.