All the main "brands" make very good saws. As with nearly all tools, bigger is better mainly for the power you get and as put forward by
@Ollie78 . For you as the operator it comes down to 2 things really, ergonomics and space. If you are tight for front and back space for the machine then the choice comes down to the Bosch GCM 12 range with the clever multi pivot arm as this needs no space behind it really. Otherwise it comes down to the most important factor the ergonomics, you should go along to your local factors and play about with the display models and not just for a couple of seconds - go through the motions of using the saw 10 to 20 times one after another and see if it feels right. Turn on the various buttons and reset the trenching height and flick the buttons for light and laser etc and move the stops. The one that feels the most natural is the one to get. If you base the purchase just on cost and pick one that feels not quite there instead of the one that felt good you will regret the purchase evermore.
I am lucky in that I have 24/7 access to a big Festool beast of a machine and recently was given a small 8" blue Bosch, having had a play with it, I will be using the little baby blue a lot more than the Festool and that is down to ergonomics even though in terms of build the festool is on another level to the Bosch. It just feels better; this is also why I have no festool routers as to me, the Triton and the Makita machines feel much more natural in my hands.
HTH