For CFS's I find it hard to say anything wrong about Rise of Flight, it's amazing and the dev team is probably one of the most motivated and dedicated I've ever seen!
But, I have IL-2 1946 with the HSFX mod 4.1 (apologies if theres still something against posting IL-2 mods)
and the amount of offline campaigns is amazing, I'm flying in the White Sun-Blue Sky campaign that focusses solely on the Flying Tigers (Which I have some strange attachment to) with all the settings set to hyper realistic.
that being said, I feel great for having 15 kills and counting
DCS World looks to outdo anything on the market in terms of depth and playability though, I like the module options and I put in my pre-order for the Mig-21 Fishbed module