I installed four 1383 "8-gun" LED bulbs from MarineBeam in the cabin this past weekend and took Libations out for an overnight at anchor. My impression of these LEDs is positive. The light quality is only a very slight bit cooler than the OEM incandescents...almost indiscernible...and the light output seems to match the old incandescent bulbs pretty well.
The frosted incandescent bulbs are bright to look at and can be somewhat annoying depending on where one is sitting and the direction that the fixture is pointed. The same is true for the LEDs but because of their intense light output (and no frosted bulb) they may be just a bit more annoying. Not a huge problem but it did make me wonder how the 1-1/2" LED would have performed...tucked up into the fixture another 1/2 inch may tend to hide the bright LEDs from one's eye.
I attached some photo files that show the 1383 LED (2-inch length).