You're right, don't know why but I never think about the OM2 SP. And while I think about it the OM3 has spot too, right? I would go for an OM1 anyway, it feels like the Leica M2 of the SLR history to me. Small, fast, mechanical, small, fast, reliable, and small and fast. Everytime I grab another camera it feels so akward to have the speed dial on top instead of right on the lens barrel. Pure genious.
Much as I like my Pentax MX's, I find the shutter control on the OM-1 to be just right. The MX's (on top) is stiffly detented and too short, so is hard to move quickly. I recently handled an OM-1 and once again marveled at how just plain good it is. One of these days...
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.