What was airline training like?

It does depend a lot on the airline you get hired at. AQP is probably easier than traditional 121 training. Some airlines do that, some don't. I've only been through AQP so I can't say for sure, but AQP was still hard enough. Some airlines are used to dealing with piston pilots where this is your first airline job. Other airlines usually only hire from the regionals or other, similar airlines. I got hired at an airline that was so inexperienced at hiring non-ATP's that the guy who did my checkride literally had to look up how to do it, and what he needed to check on my end. The entire training, even though it was AQP, was geared towards people who already had experience in jets and all my instructors treated me that way too. So it was sometimes a struggle to keep up. I was good at the hand-flying part, and did pretty well in the maneuvers training - sometimes better than my sim partner, who was like a 30 year captain who'd been away and was trying to requal. But procedures were tough. I'd spent my entire 1,500 hours leading up to that point hand-flying. I'd only used an autopilot of any kind for real once, and that was mostly just my instructor showing it off for me before my flight school deactivated it in that airplane (it was the last airplane they had with an AP). So when I started airline training, my first instinct whenever anything unexpected happened in a sim was to switch off the autopilot and hand-fly. That's even what the guy who made the "children of the magenta line" video said to do! But that's probably a really quick way to get yourself kicked out of airline training. I almost failed a few sims because of doing that. Make sure you learn the actual procedures and if "autopilot... off" is not one of them, don't do it. Studying and practicing flows and procedures was about 90% of my training. And you're going to be doing that about 99% of the time when you're not eating or sleeping (and even a lot of the time while eating). There's not a lot of real downtime in initial airline training when you're coming from a piston background. It's going to feel like starting over, with only a month or two to learn everything. But it's obviously possible.