Mine is the one in Fallout 3/New Vegas. It just looks so beefy and tanky!

Fallout 2 Vertibird. The thing just looked cool and had an appearance similar to that of an insect. It also seemed more realistic as the Fallout 3/NV Vertibird didn't have a cockpit which can be seen through. Not that I despise the Fallout 3/NV Vertibrids, I think they should've added two variants, the Fallout 2 Cargo variant and the combat/transport variant in Fallout 3/NV.

The Fallout 4 version was an interesting take. At least it felt not like a dropship, but rather like a gunship more or less. The interiors of certain vertibird mods for F3/FNV didn't really interest me a whole lot. I have yet to see what the Fallout 2 vertibirds look like. Maybe I oughta give a search for it. But after seeing the quad-rotor vertibird transports from the Frontier mod, I imagine it is a hint of something, or maybe just fan-inspired? I don't know, but If I wanted a dropship, I'd just use a pelican, which is from Halo, but I have modded some of my own variants ingame. I like the F4 vertibird the best due to how compact it is.

Yes. The combat transport variant:

Spoiler:

Fallout 3's vertibird is comfy. If my character could ask Sarah Lyons if they could take a nap after converting Adams Air Force Base into dirt, you would know my left mouse button would look like it had been crushed by a 30 pound sledgehammer. Shame that it was only available for the ending of that one quest in Broken Steel because it would've been so fun to use it for fast travel around the wasteland. Fallout 4 got that element right, but it's a shame that it's vertibird looks like it was designed by a five year old with aluminium foil and a stack of pencils.

Fallout 2 Vertibird, look how menacing it is.

Spoiler:

In all seriousness, FO2's Vertibird is the original and the best looking aircraft. Vertibird from FO3 and NV is still a fine looking machine, but it's bulkier and simplified with less details.

Vertibird from FO4 is the worst of the three and weakest with open cockpit.

So, yeah. I have seen both designs posted by other users here, and even if I'm one of the very few that has taken a liking to F4's vertibird design, I do admit there can be certain features that can be improved upon, and make it less morbid, who knows? Maybe I might make my own version of a vertibird one day. But hot damn, am I ever liking the quad-rotor vertibird combat design that which guan12 linked and posted. And if that's a design that will soon see flight in the Fallout Miami mod, so be it. But yeah, I like that quad-rotor design too. Though in my brutal and honest opinion, I never was a big fan of vertibirds at first, as I usually refer to my jet-propellant VTOLs and whatnot, and after seeing the Fallout 2 standard version, kinda looks like a well organized raider gang's choice of vertibird.

Fallout 2 is my favorite game in the franchise, so you'd think that the vertibird design from that game would be my favorite. It's iconic to be sure, but it's not my favorite. My favorite would have to be the design from 3/NV. With its heavy armor plating, it's the only one that looks like it could actually withstand a barrage of fire from wastelanders below while transporting troops. The vertibirds in 2 and 4, while both cool in their own rights, look more like light cargo transport in comparison.
I love all the vertibird types we've had over the years, admittedly because of the love I hold for the V-22 Osprey aircraft, but none come close to 3/NVs. Say what you will about 3 as a game or Adam Adamowicz as a concept artist, but boy did he create an appealing vehicle.

^ Same, the Fallout 3 Vertibird has always appealed to me. Heavily armored and armed with its assorted gatling lasers, miniguns, missiles and mini-nukes. It for sure has the appearance that suggests it can take a beating while swooping troops in and out of a combat zone, all the while putting some heat down for air support.

I still like the one in Fallout 2 as well, since it has a more pure troop transport vibe to it while the one in Fallout 3 is like its armed to the teeth successor. A natural evolution similar to the Huey to Cobra helicopters. The Fallout 4 one is... not terrible, but compared to 2 and 3 I feel it's almost like a downgrade aesthetically.

The Fallout 3 Vertibird takes the cake for me. Fallout 3 was the first Fallout game I played so I've got to go with the Vertibird in that game.

Not a topic but the best tiltrotor at the umbrella Corporation.