Definitely agree here, although with opposite experience. When Destro was the general best-simming spec I tried it, but generally found that I wasn't quite as effective in raids as I was with Affliction. I had played Affliction for so long that a huge part of my rotation with it (including switching on-the-fly between Shadow Bolt and Drain Life fillers based on fight situation) had become completely automatic, and hence I could use nearly all of my conscious thinking to become aware of the fight progress and the other players. While I practiced with Destruction enough to get fairly competent with the rotation, I would have had to persevere a lot longer to get it to the same "instinctive" level as I was with the Affliction playstyle. I could generally match my Affliction DPS on average, but I found myself standing in fire rather more often and generally not being quite as useful in calling things out. I went back to Affliction after a few weeks.

Obviously for me it's lovely that Affliction is the "best" spec now, but I can certainly understand and support other warlocks who find Destruction (or indeed Demo) still works better for their play-style and brain function.

That's really interesting and just goes to show it's the player and the way they treat the spec. I've always been Affliction and my raid has five warlocks in it (sometimes six ...) - myself and the other two Affliction warlocks have been better than the Destruction locks this entire tier of content and we still are.