Actually, the M400R2 has been discontinued for quite some time.  2017 if memory serves me correctly.  The M250R2 will be next as many utilities are installing LEDs, and orders for the M250R2 will dwindle more than they already have.  I'm sure GE is keeping them in production as an alternative for municipalities that have not yet switched to LED.  But one day, they too, will be rare.  I got mine still in the box.  I've used it for a little while as a light for my bedroom, but never outside.  Also, Mike of McCann Lighting restored an old M250R1 for me (Fixture and Parts provided by me, Labor by him).  I traded his services for a brand new, hot off the press M250R2 (It had literally been built the week before he received it.)

I admit that I am moving slowly over to the LED Movement.  I HATED LED until my utility started using the LEOTEK Green Cobras.  They put out a Warm White, and when you look down on the street, it looks like a DLX White Mercury Lamp. 

That's because most members are not LED fans.

I mostly see them in Coastal towns and Cities.