I have done a LOT of testing and work with LED lights for the home: My adventures in LED home lighting
The best MR16 bulbs , by far, are the Philips Endura 10 watt / 490 lumen ones. I get more light (actually measured) in the rooms than with the supposed 900 lumen/50 watt halogens. My house uses 42 of them. Two rooms are lit exclusively by them.
5W bulbs will really suck at socking out the lumens… believe me, I’ve tested lots and lots of them. The best ones that I tested were less than 200 real (not Chinese) lumens. Most were in the 135-150 lumen area.