Just saw this. I couldn't get on with the Kenwood, I had a DNX520. Things that annoyed me where the slow start up, slow response to touch screen, looks weren't great and the lights didn't work with the light switch but it could tell when the lights were on to switch to night mode. iPod cable was terrible too.
I moved on to an RNS510. Much better.
I believe a lot of this was addressed in the 525 so hope I'm not P-ing on your chips, just saying what I experienced.
The kenwood will be easily to use on a custom system I'd imagine.