EDIT: We ended up choosing a different skybox with clouds; one we could all agree on. This poll helped massively though in finding out what others liked. Thank you.
Every skybox depends the first one:
A.i would say is more realistic and makes the game more realistic and detailed.
B. I would say with this one seems more cartoony style and more calm makes the game more simulator type, but makes the game clear and unique.
Though the game seems to be a low poly type game, I’d suggest using Skybox A, due to the fact it gives a very good and detailed look to the game that Skybox B can’t provide.
The simple gradient of skybox B matches perfectly with the games style, the fact that skybox A looks more detailed shouldn’t be a factor in determining which skybox to use. The only downside of skybox B is that there’s no clouds, though it shouldn’t affect the games design as it can be seen as a clear blue sky (common in this type of setting, or pretty much anywhere)