Do any of them actually work? I read the caravan one doesn't work. I'm playing Khergits but using a all cav army is fast anyways so I don't know if the 10% works or not.
Aside from working or not my thoughts are, from a warband perspective:
*1* The Empire bonus could be amazing..... if hit and run seige'n worked like in warband..... but I don't think it does, seems just siege engine speed might not help you siege without them catching up to you, so far it takes a long time and it's hard level up engineering, but it'll take a more developed game for me to see how good it is. This was my number 1 choice but I soon realized I won't be painting the map anytime soon.
2 The Khergits 10% speed is useful for the whole game and there's not a very strong pathfinding skill/perks. I'm curious if it works with extra horses in inventory = or greater to foot units, since a tool tip says foot spoilers will ride extra horses on campaign map..... but again I can't tell if all the things in tool tips or the perk actually work right now.
3 Vlandian is good since we don't have good trainer effects (the leadership perks are very weak), though once you've got your army leveled it's not useful unless you run out of bad dudes.
4 sturgian/britanian these terrains pop up more the I would have though, lots of snowy places and chasing empire guys through forest in middle of map.
I'd rather just take the mounted bonus but these seem better then I assumed at first glance.
5 Caravan-man ...... it's basically saving 4k (when it's fixed and works) for each caravan you make and I assume 10% more profit.... it's just not that hard to make 4k more to make caravan and once you are stabilized extra money becomes trivial since you can get so much through beating lords, I'd rather have a skill that benefits the long game.
So for now it's the Khans way for me, but maybe when the dust has settled the empire bonus could win out.
It's also important to know that the culture background also changes the attribute and focus points of some of the parental/first options.