I am starting the game and would like the most trouble-free experience possible. Which class should I pick?
Expert Soldier allows you to start with a very very strong merc you can hire in Westside at ridiculously cheap upkeep, allowing you to capture a lot more people a lot faster and sell them for profit. With just five melee training sessions, Einar gets to 80 melee, allowing him to start at the front of the combat, with a whipping cane ready. Expect Soldier probably also gives you 80 melee already or close enough so you can start at the front of combat. Giving him your best gun should allow you to take on more fights earlier with a lot more captives. Add three other hires, like Bud, Jack, and then maybe with the spare money Ayden so you have a fully ready quartermaster right from the start. For the lategame though, Einar may not scale as much and lose out to some NPCs. Specifically, Cassius, Milou, Aaron, Clea in the right position, and your sons properly built once you figure out how the nursery works.
The best for lategame is having no expert classes. Expert classes are primarily for roleplay. Taking three levels in a class is a lot of points because the last level is 120 points. 120 points that could have been spent on picking traits. Yes, not even businessman level 3, which is a scaling class, because honestly, at day 1000, would having 25 million instead of 18-20 million matter a lot? If you are a Tier 4 subscriber with MoR Enhanced start, sure, take an expert class. Enhanced gives you 750 points. You have a lot of spare points. But normal start is 280 points start. You are going to have to give up some things for an expert class. Again though, this is a roleplaying game. Roleplay however you want and Expect classes adds to that.