The most memorable part of CloD for me was the ballistics, it's almost like you feel your inputs flex the wings and mess your shots up, you have to be smoother have more finesse to hit things. Not only that but the flashes and holes it leaves in the plane just look way more detailed, damage model more detailed, you can actually see which internal components you damaged. I'm not a pilot, I don't know anything about flying I just like to see things blow up.
I think as a flight sim game BoS is waaaaaayyyyyyyy ahead of CloD with its archaic interface and mega niche servers. CloD has nice small details like picking the type of ammo you fire, that used to be pretty fun.....but compared to the extra details BoS has? Nothing.
BoS is superior in every other regard, you don't feel like flying on rails, the graphics and engine murder CloD although CloD's cockpits/clouds still look impressive. Flying itself is way easier in CloD, on rails as they speak...managing engines not so much. Engine management more complex and less forgiving in CloD but nothing like DCS obviously; one could say engine management in BoS is super lax.
Disclaimer: I don't know wtf I'm talking about, just my opinion.