I hate strapping stuff to my bike. I like a light bike because it handles better, so loading it back up again spoils that. Especially with a rigid bike – it doesn’t skip over bumps when it’s got bottles and a pack on it.
I’ve experimented many times in the past and I’ve come to the conclusion that a Camelbak really doesn’t bother me at all, so I use one for convenience. I may try again with a small saddle pack in the summer but then that means either buying another multi tool or swapping stuff over which is a pain.
On road, handling of bumps isn’t an issue so I go with jersey pockets for phone and keys, a saddlebag and frame pump.