I’ve had both... I’ve seen on this forum how everyone goes bOnKeRs for a Dart Marlin... So I’ll quickly just type from the other side of the spectrum.
From what I have seen from Dart, they don’t offer color matched short screens. I prefer the color matched screen because it sort of “cleans up” in front of the gauges and “completes” the look, to me, ascetically. So that’s all looks over function in my case. But I like it a lot.
Also, the way the Triumph screen mounts are behind the headlamp ears of the bike, with 2 or 3 screws that mount “from the inside”... While the Dart (while still nice, so relax everyone), typically mount from the outside of the headlamp ears using the one large headlight aim bolt, and utilize a metal tab that presses against the bike’s headlamp ear so the wind from riding can’t push the shield all the way back to make contact with the gauges... So, ascetically it isn’t as much of an integrated look as the Triumph.
The shorter Triumph body colored screens obviously only offer minimal wind blocking. If you don’t want the screen for that nice clean look, and would actually want it for taking wind off your chest, then you would need to buy one of those giant police riot clear things that stick up 20 feet in the air, obviously... Since you sit more “on” a Bonnie, rather than “in” a bike like an American cruiser style bike.
Lastly, some of the Darts give the bike a sort of Triceratops look with its shape. Vs the traditional “cafe” look that I can only assume the OEM body colored ones are shooting for, and do well.
To recap... If you are looking for more of a FUNCTION over form, I would recommend the Dart.
If you are looking for ascetics as the primary reason while changing the wind slightly towards more comfortable, then I would choose the Triumph. This recommendation is only when comparing a Dart to a Short Triumph screen.
Lastly, Triumph offers the short screen in body colored, clear, or dark-tint, as you probably already know... While I believe they also sell a medium height and a Tall height screen as well, but just clear so you can see thru them... I have seen the tall clear on a T120 in person... And it mounts nice and clean, and surely must give a much noticed relief in wind. Any bigger of a shield and girls would make fun of you at stop lights... And no one wants to see that. Not on a Triumph #Chips