With LED bulbs there is a process called "binning" or "bined" bulbs. This binning is a process of careful selection of the bulbs based on certain specs and matches output, color and a number of other factors. Bined LED's cost significantly more money and are generally used by the higher end bulb manufacturers. There are also BIN grades. Orphan bulbs are the ones that don't meet the various BIN criteria and they sell for very, very little money when compared to hand selected binned bulbs for use in higher quality bulbs from the likes of reputable manufacturers. I know Sensibulb buys top quality bulbs as does Marinebeam and I also know that both companies reject entire lots...They could be from different manufacturing runs, of the same design, from different manufacturing plants. A lot of companies outsource actual production, and the circuit board design is identical as are most of the components. It is like when a computer manufacturer uses Western Digital harddrives for one production run, and then switches to Maxtor or Seagate harddrives for the next batch because the WD drives were more expensive or not available. Almost identical specifications, but slightly different components.
While the bulb looks identical the research I have put into this over the last month or so falls more in line with what Jeff from Marinebeam said above. While the physical board and electronics may actually be assembled in the same factory they can still be built and assembled to different spec. One bulb may get the top quality binned bulbs another might get mid quality bined bulbs and yet another might get orphan bulbs which meet none of the binned requirements. From what I've learned SMD orpah bulbs can sell for as much as 80-90% less than a quality binned bulb so it stand to reason why a company selling orphan bulbs can also sell the entire bulb for considerably less..
I've ordered yet another bulb to add to the mix. This time it's the big brother to the Marinebean MR-11-6. it's called the MR-11-10 and it sells for 27.95. It has 10 SMD LED bulbs on it, as opposed to six, and I'm guessing it will compare nicely to the Sensibulb but for about $9.00 less.
By the time I'm done I'm going to have to buy more light fixtures for my boat!!
P.S. Still waiting, day seven, on the bulb from Superbright LED's. Their shipping and delivery is poor IMHO. I received both the Sensibulb and the Marinebeam products within one day or two days on standard ground shipping which means they both ship the same day..