I never used a lock until I got a berth in my present marina. They aren't all that common in Australia. The one I use is at the entrance to the marina, and it works very well.
Each berth holder is issued a remote control to control the lock, giving us 24/7 access. A button for each gate; one to equalize and open the other gate; and an emergency stop button. All very simple. It is a bit slow taking maybe 10 minutes to get through, depending on the tide. Opening the sea side gate requires a pedestrian bridge to automatically retract, along with the necessary safety gates, flashing lights etc, taking a bit of extra time.
The lock is about 80 feet long allowing 2 boats the size of mine, although it is rare to get more than one boat passing through at a time. The only design problem is the horizontal I-beams on each of the gates. I have heard of boats drifting forward until the bow rail touches the gate. If the lock level is rising, the bow rail can get caught under the I-beam while the water level rises.
Not good. Obviously its a good idea to keep your distance.
There are ropes hanging every 4 feet along each side which can be used to hold your position, although not a good idea to tie off when the level is dropping, for obvious reasons. (unless you want to do a quick bottom check)
What are your local locks like? I have heard others are hard to deal with singlehanded etc, but this one is a breeze. (actually no breeze, making it easy)
Sorry -no photo's handy.