I've been training the AP on my freeway route to and from work for over a week now. There aren't a ton of Teslas in Houston, so it is going to take some time to refine the AS, given the deplorable condition of the roadways here. Same issues as others have reported, lane drift on curves, "searching" behavior, etc. It hasn't tried to drive off at exits or get confused by losing the right line at entrance ramps.
I will consider it a complete success when AS is able to take my dead man's curve entrance ramp at speed. For locals, it is the entrance ramp to I-610 West off of 59 North, an elevated ramp with a hairpin turn. I started training the TACC months ago through human intervention and now the AS gets the same treatment. There's usually no traffic at the ungodly hour I drive to work, so I let AS do its thing on that curve the first few times. After it made a bee-line for the retaining wall, I decided that it needed a little more tutoring.
I have played around a little bit with "summon", but it seems more like an interesting parlor trick than something I'd use on a regular basis. I'm so paranoid about my new car, I rarely park it next to any other car; so tight spots are not an issue for me. The whole dysfunctional Homelink saga at my townhome renders the one interesting feature of summon of no practical value to me.
I haven't enabled the auto lane change feature yet. That's the next step for me to play around with. Since AS still seems to be learning my oft-traveled roads, I have low expectations about how successfully it will navigate those maneuvers. Just a little more testing of features and I'll finally be able to demo the car for my colleagues, who have been clamoring for an up close and personal since December.