WWIIOnline is nothing like AH though.
It has its similarities. The tanks are like the AH tanks of old where you have multiple crew positions and the driver has to change gears. The Infantry aspect is great and of course has no parallel to AH in any way. I found flying in AH easier than WW2OL. It takes much more manual input to even get off the ground in WW2, but you don't find a lot of air to air in there, mainly CAS. The graphics are closer to AH2 and some of the action cartoonish, such as Infantry jumping off 3 story buildings like supermen to the ground taking off running and a 0-60 run that would rival any olympic sprinter.
The game function though is completely different, there's no base (city) sneaking, there is a command structure that defines offensive attack objectives and defense objectives. So you could say they have a totally mission oriented structure, no freewheeling lone ranger action. The map is huge, pretty well all of Europe, but with the mission oriented play the fights are easier to find since they are controlled by the command structure.
There's a niche for all in both AH3 and WW2OL. I play between the 2. When I want to play total ground war then WW2 fills that niche and the combined AH3 Air/Armor war has no match in WW2OL.
AH3 is still my favorite of the 2 and I jump over to WW2OL if I feel like playing Infantry.
Learning curve is just as difficult if not just a bit harder in WW2OL than in AH3.