Spark is a rather slow machine and in sport mode I hate the tilting camera. There is no way to turn that off. However in P mode turning off the obstacle detector will double the speed of the Spark. (and no camera tilt)
Gee...if you don't try really hard, you're going to learn something new almost every day..Not sure if It's going to change the way I fly...I like to smoke out and back and film slowly but it's nice to know there is another option. I think I heard somewhere that obstacle avoidance off is a battery saver too. I'm sure we've all enjoyed watching Dustin Dunhill's epic marathon distance videos. It seems to me he does that on some of those downright scary returns.
And if you're flying beyond your actual visual acuity (I really don't believe people can actually see the drone at 1km) then turning off the OA ads to the risk of harm to others since the drone will simply fly into things. (And no, the fpv view isn't sufficient to avoid that...)
I would not hesitate to buy a new fancy drone if it DID NOT have OA. The reason is OA does not always work, rarely works with thin branches or straight wires, power lines, and when I fly without OA I am much more careful. Don't think for a minute that OA will help protect you from a fast flying object in your path like another drone, a bird or projectile of some sort, like a ball. It has its limits. But the expertise of a good pilot is the best OA system.