I went for one of the more "expensive" units. It was originally grouped with 2 other models on Amazon - the other 2 had knobs. I was going to buy a knobbed one but realized I haven't used a DVD or CD in 20 years or so.
There are buttons on the bottom but I use the steering wheel controls mostly. Everything is included but it may need something for the rear screen if you have one. I didn't bother hooking it up.
It has carplay for apple that works great - wireless. I was also able to download Netflix, YouTube TV and Amazon Prime to the unit and stream from my driveway. I am sure you can tether to your phone n the road if you want to watch tv and kill someone.
I cut the supplied harness's reverse line as I have the camera in the mirror. In my setup, the screen would go black in reverse with the unit, now it just stays as a normal screen (the mirror still works).
The sound was way loud at first - I had to go in the factory settings using code "0000" and tell the unit that I had an amplifier and adjusted the "gain". I didn't even end up using any of the 3 USB ports - just wireless. So, install took less than an hour in total. Simple plug and play.
Edited****
CarPlay is what apple uses for texts, calls, navigation, music apps. There is no web browser. The unit itself has chrome installed.