Topstitch needles have a larger eye, which makes them easier to thread. I used to use Microtex because of the sharp point, but once I used a topstitch needle and discovered how much easier it is for me to thread, I made the switch.
Edit: I want to mention, though, that I use a size 80 needle for piecing (70 or 75 for invisible machine applique). I don't see a need to use a size 90 needle, especially with a 50-wt thread. The needle holes will be unnecessarily large.
Last edited by Prism99; 10-22-2016 at 06:30 PM.