Now the online evangelists have had their say, here's an opinion from an ex onliner who now prefers offline
CoD has advanced a little since initial release- for offliners the reduction of the 'f16 rolling behaviour' of the AI is one plus point- there has also been some work on understanding of how to apply skill levels by mission builders in missions to get more believable results.
Comms are still very limited
The campaigns that came with CoD were ' somewhat lacking' to put it politely.
There are missions/campaigns being written- not many but there are some good one out there. Airwarfare is the one stop shop for user generated stuff
http://airwarfare.com/sow/index.php/...line-campaigns
There is also a rather good commercial campaign available
http://www.desastersoft.com/en/product-wick-dundas.html
demo available

- if nothing else i'd suggest trying this demo as an example of the way CoD offline play could develop
These are static campaigns
there is at least 1 WIP dynamic campaign engine in progress
http://forum.1cpublishing.eu/showthread.php?t=25076
Overall CoD maybe behind a full DBW modded install of IL2 in several areas but it does do things tolerably well now (imho). As more is discovered in how to use some of the mission builder features to full advantage (and this took some time in IL2) and the devs finally providing a more functional comms system.....