Ordered an Ultrex from John Jones on Monday and got it yesterday (80lbs/45 I pilot).
Rigged it yesterday afternoon and other than setting the foot pedal angle install is just like a Fortrex. Indexing the steering (setting the foot pedal angle) isn't hard but I had the read the instructions a few times to wrap my brain around it. Pedal fits in the Ranger tray no problem but I think most people already know that. If you put the front of the pedal parallel to the deck it is 5 inches tall which is roughly 1.5 inches above the deck.
I fished it for a couple of hours today and over all it's pretty much as described. Steering is maybe a little to quick and sensitive vs my Fortrex but I didn't adjust the steering tension. Turning input via the pedal is instant. I also found the foot pedal angle MK says to use to be too flat. I'm used to my fortrex pedal being up in the front when going straight and MK has you set the pedal to be parallel to the deck of the boat which is way to flat for me. I adjusted it to feel like my Fortrex pedal when I got home this afternoon (and cranked up the steering tension). Not sure if this angle will cause problems down the road with spot lock or ipilot but the motor seems to still have the same turning degrees.
Spot lock works great and it is a quieter than I was expecting. I actually had to look down and see if the head was moving a few times. You can easily spot lock with your foot as it sits above the top of the recess tray. When I first hit it you could feel the boat move as the motor did it's thing but once my boat swung into the wind the adjustments were so small I couldn't feel them. But over all the motor is really quiet.
I don't like the handle on the cable you use to deploy and retract the motor. I like the big red one handle because I could put the hole your fingers go in where the bounce buster hits the deck and not worry about it flying around when I trailer. The MK handle works great, though.
I stepped on the button for cruise control a lot as I naturally stand really close the corners of the recess on my 519. It didn't do anything as I never really use constant (so it engaged but because I was set for momentary the boat didn't move).
I really, really like that it has a light showing when its getting power. It seems silly but I sometimes forget to flip the breaker in the back and now it's easy to tell if it's got power.
One thing I didn't realize is that to use the jog functions on the remote you have to run the MK heading sensor. It comes with the Ultrex and it is easy enough to install but wasn't going to use it until I read the install manual. It needs 12 volt power but communicates with the Ultrex via blue tooth. I installed it next to the cup holder on the trolling motor recess tool holder.
I didn't use the remote much today so I can't comment a lot on it.