Thanks guys, to clarify I have the stock Ultra so the Eggrider and presumably the 500C will work.
I've been using the Eggrider until now and while I love the functionality (detailed data logging, programming the motor with my phone, etc), it's not much of a "display" for me. I don't look at the display much when riding (especially since tuning the motor such that I can leave it in one mode for entire rides) so I thought it would be fine. But every now and then, I would like to glance down and check my speed or battery level, or verify which PAS I'm in if I do change...and Eggrider just isn't very usable for that. I'm old enough now to need reading glasses just a little bit and that print is TINY. And when wearing polarized sunglasses (of which all mine are) if my head is cocked just wrong the display disappears completely.
So I do think I'll give the 500C a try. I can always slap on the Eggrider temporarily for "test rides" to evaluate tuning, etc, when I want to datalog. What I'd really like is Eggrider functionality in a 500C body. It's a bit disappointing to see the displays from Innotrace are based on the Eggrider body. If I ever upgraded to one of their controllers, it looks like to have a display with the latest/greatest capabilities, you'll have one with the same basic problems as the Eggrider. It looks like they made the print for speed a little bigger but....