All in all, 360 has got some fun stuff for all ability levels. It's an especially attractive option if you live on the Kitsap Peninsula. The fire road loop and the non-bike-specific singletrack are OK, but the real jewel is the bikes-only trail in the northwest corner of the park--nice singletrack with a lot of optional features scattered about. The one thing I will say is that the short uphills are steep enough to break up the flow a little, but it makes for a very good workout in not a lot of time. I don't know who put all the building work in on the bike loop, but it's much appreciated! It's an impressive piece of work to cram so much trail into such a small space (though the 20 miles mentioned above is a really generous estimate). 

Worth the trip to come check it out if you're nearby.