I have the Janome 300E and LOVE IT! I have not had a single problem with my Janome and have done a lot of embroidery. I have embroidered on cotton, knit, denim, slinky stuff, furry stuff and stuff I've forgotten I've embroidered on and my Janome just keeps plugging away!
I do the the Customizer program but don't use it. I prefer to use Embird. At first Embird is a bit difficult to catch onto, but I purchased the tutorials for Embird and followed those step by step and now I can whizz around Embird like a pro.
Good luck and keep us posted on your progress!