If you are using a normal tv (as opposed to a monitor), your tv will still be the main source of terrestrial or free view channels. However, you can get streaming versions of terrestrial channels via native android apps like BBC iplayer, itv hub and apps like tvcatchup.
A sky subscription gives you guaranteed access to their portfolio of channels. This is particularly true of sports.
Plug and play? Well, not quite. This is true of all android tv boxes, not just those supplied by droidbox. There can be some frustrations. However, there are plenty of guides, you tube instruction videos, how-tos out there. Plus if you buy a Droidbox you get access to this user community who I have always found helpful and willing to offer advice especially to new users.
So in conclusion, if you are going to buy an android to box, then there are few better than those supplied by Droidbox.
I cannot speak specifically for the gamers edition as I don't use my box for gaming.