Most of them are pretty short, so you do have to tilt the bottle to reach the stuff inside. This can be a pain (and quite the spill risk), especially with larger bottles.
Also, it is really importantly to
completely rinse out not just the glass tubes, but also the rubber tops of those after each use. The EO will eat right through them - ask me how I know.
Even with regular rinsing, I find that the rubber tops fail pretty quickly due to even brief reactions with EOs or FOs. Too bad, because I have tons of them from some vitamins that we regularly buy.