Does anyone use ground vehicles?

I have more fire power with 3 soldiers and they can reload

Yes I use them, especially in the first half of the game. The Aspida even in the later stages, for me the best tool for scavenging sites, if something went terrible wrong or I just want to easily farm pandorans for food or mutagens.

I wrote something about APCs in another thread (a bit down in the text and then additionally open the optional textbox):

I use vehicles all the time! They’re really good force multipliers when trying to fill out your B & C teams early on sense it doesn’t require as many soldiers if you use vehicles. Now obviously you won’t likely be using them as part of your main A team as you’ve already pointed out 3 veteran soldiers will provide more firepower… to me that’s not the purpose of vehicles. They bring utility and roster flexibilty allowing you to spread out more on the strategic layer.
Now I would like to point out that I don’t typically build them or recruit them (except for an Aspida) but I like to use the ones I get from the special scaveging missions which I usually find 1 or 2 this way.

I’ve been messing around with an 4 man squad which is 2 assaults, 1 infiltrator for recon and a tech support with a scarab or an armadillo. If you bring the tech you can use remote control to fire the main weapon while zooming around and dropping your shotgun assaults out the back door to blast a pandoran and then jump back in. Makes mind control useless and you would need 5 or 6 pandorans blasting away to wreck the transport before you could retreat for repairs. Playing on veteran while I figure out the strategic game so maybe not as viable with more/tougher pandorans.

Immunity to mind control and infinite amount of cheese if you bother to pop-out, take a shot and get back into vehicle again. They make scavanging missions rather trivial, at least at the start to midgame, didn’t bother to use them later.

To be honest I completely forgot there were even vehicles in this game. So no, I never use them.

I mod the game to make then take 1 place at air craft. I am using those with secondary teams.

They are not so useful at some maps as they can’t destroy objects even you think they could. So the movement is limited. Scarab missile is good, armadillo minigun sucks like every minigun in the game (not turrets, turrets are awesome), mutogs are weak at attack and defence, synd one looks good but not used yet.