With all the releases, I do find myself playing more stock than I used to, up to 50% of the time even. I still play the mods more, partly for the planes/terrains available that are NOT stock, partly for the more accurate way they're generally done, but that used to be almost NO time flown stock.
Ironically, the mods are a victim of their own success. Other than my total conversion mods like ODS, Vietnam+, and NF4+, I just have one modded install (SF2 in this case) with EVERYTHING. Partly for simplicity (post-patch), and partly so I don't have to remember where each mod lies. However, with that mod folder nearing 70GB now, loading times are a big PITA! Plus some of the mods don't seem to work right with recent patches (many date from the early days of SF2 or even are ported from SF1), so I never know if I'm going to get a CTD or some other odd behavior...so if I only have a few minutes to fly, I usually pick stock.