Which can mean that you ask for electronic strips with the certain layout/look as an interaction device, you get it , but you do not get desired functionalities because they are enabled by another module/sub-system that you did not ask for. Of course this example I give is a bit of exaguration just to ilustrate what can happen during this process.
Glad to hear we're not the only ones to have bad experiences with that sort of things :-p
Anyway, in Brussels, we use an in-house developed system at the tower, which works quite well for more than 8 years already.
More info at
Belgocontrol - Airport Movement System - AMS