I'd agree, but if you start to lower one side more than the other, the plate slides a bit, further lowering it, and just makeing the situation worse. Collars are easy enough, but its totally personal prefrence.
True, but most plates have an outside ridge, makeing this a moot point.
Top over, easier to grab.
Plus it can get annoying if you drop them all the time. And, it shows respect for the equipment, as it can chip/break/crack if you drop them. It also depends on the floor too. Softer stuff, like rubber mats makes it easier to let the dumbells down faster.
I also don't like people who, at the top of every rep click the dumbells together (ie: on a DB bench press, bringing the dumbells all the way together at the top so they hit each other and click) I kinda got use to it tho.
I want the last minute of my life back.