I found the in house software quite good, the stadium map allowed you to easily select the area you wanted to sit in and then you could just pick the seat you wanted in the drill down. It would also give you an idea of what the view from that seat would look like so if a post was completely blocking the goal you could choose another. Perhaps that could be another reason why they've switched, people will buy the ticket not knowing just how restricted it will be.
The ticketmaster map is the whole stadium in dots for the seats, there is so much information that when you try to zoom in and move around it doesn't respond immediately and by the time it does you're already at grass height somewhere on the pitch (why doesn't it snap to the stands regardless?) and you have to zoom back out and try again. This might feel different when using a normal PC but I'd imagine most people use their phones/tablets to do things like this.
I assume ticketmaster deal with the printing and sending of tickets now allowing the club to get rid of any staff who used to deal with this which for what we've got in return makes it even more sad.