Now, question for you twin drivers....
What's your thought on a bow vs stern thruster with twins? With a twin set up it's pretty easy to move the bow, but almost impossible to move the stern.
I find it the other way around. I think a stern thruster would be absolutely pointless on my boat, as it's pretty easy to move the stern sideways with the engines. Moving the bow sideways is harder though, so a bow thruster would occasionally come in handy. This may be different on an express cruiser type with a very shallow forefoot where it'll pivot further back. I'd say the pivot point on my boat is somewhere between 2/3 and 3/4 of the way forward, so in many cases, you're pivoting the stern around the bow more than anything.
When backing into a narrow slip, for example, you can move the stern around pretty easily. But to move the bow a foot sideways, you generally have to move the stern around more than that. To move the bow to starboard by a foot, you'd generally have to move the stern to port something like 2 feet (as the pivot point is typically forward of center). So you often end up doing things like turning the stern to starboard a bit, then pivoting the boat (moving the stern back to port) and adjusting from there.
A bow thruster with a twin is useful in my mind in a few situations. The biggest 2 in my mind are backing into a narrow slip where you need precise control of bow positioning without a lot of room to move the rest of the boat and getting off a face dock when the wind is pinning you onto the dock (walking the stern out is easy with the engines, but getting the bow out is harder, especially if you can't pivot against a fender without hitting the swim platform and there are obstacles to letting the pulpit overhang the dock as you pivot and depart).
Basically, a twin can pivot in place unlike a single, but also acts like 2 singles (with extremely strong prop walk) tied together. That prop walk is extremely useful, as you can use it to generate some amount of sideways movement much more easily than you can when playing with the rudder and thrust (partly because it works in both forward and reverse).
This also gives you good steering in reverse when having to back up for a long distance in a space too narrow to spin around. Both engines in reverse goes straight. If you want to turn gently, take the engine you want to turn towards out of gear. If you need a tighter turn, put that engine in forward briefly (but watch how long you do this or be ready to add throttle on the other engine to avoid losing too much of your reverse momentum).
As an example of using prop walk, my home slip is at one side of a basin. Due to how the water moves through the basin, my stern always drifts off the dock (towards the neighboring boat) as soon as I drop the stern line, regardless of wind. The bow follows the wind. So unless the wind is pinning me to the finger pier, the departure method is to drop the last spring and the stern line, then head for the helm while giving the admiral the "go" signal. She'll then pull the bow in fairly tight to the dock and remove the bow line. At the helm, the dock side (port in my case) engine goes in forward, followed about a second later by the other engine, then shortly after both into neutral before the turn in the fairway. Prop walk from the port engine pulls the stern back into the dock (and pushes the bow out a little), leading to a straight departure from the slip and being able to get the boat closer to the dock (for clearance to the center piling).
