I have both the Explorer and the full DCS system.
As Barry said in the other thread about the Explorer...
"It lacks a number of individual engines' features, and doesn't handle lashups, TMCC, Legacy, accessories, switch tracks, import/export, or record/playback, as well as lacking other features. It's intended purpose is to get new people into DCS."
However also from the other thread the Explorer does this ...
It will control the following functions: You can turn the smoke on/off. You can operate the horns, bells, and whistles. You can control the speed and set a maximum speed. You can control the couplers, headlight on/off, engine sound on/off, activate Passenger/Freight announcements, and you can control the sound volume. You can control up to three engines at once.
I personally have never used the functions that Barry refers to above. If the Explorer was available 5 years ago I would have purchased that instead. I decided to get the Explorer this xmas to run my holiday layout even though last year I just ran a 50ft wire from my layout in the basement to power the xmas one and it worked great. The plan was to let visitors run the train using there own phones. Nice idea but when they download the app the and add the engine, I was worried that the max speed would no longer be limited and my 500$ engine and cars would go flying off the tracks ... So I installed the app on my ipad and passed that around instead.
There is also the issue of controlling your engine using the app by touch on glass ... I'm not a big fan of this however and prefer the remote from the full DCS system ...
The experiences in running my trains with the Explorer using the ipad has convinced me that an upgrade to the wifi on the full DCS is not for me due to the feel by touch on glass vs the remote.
Given the choice today and realizing that I don't run my 15 MTH engines that often, the Explorer for me would be enough considering the prices on the full DCS system.