As there is always good advice shared here, I thought I would contribute
with some information regarding my recent install of an Evergreen ECM motor.
The bearings in the original blower motor were starting to roar, and before they seized up on a hot day or the middle of winter, I decided to replace the motor. I had been doing some research on ECM motors, and everything I read about the Evergreen was positive. Especially since I run the fan continuously and was looking into saving some cost on electricity. The Evergreen motor was an easy install, and it took me about an hour, which included cleaning the blower wheel.
The Evergreen motor runs on a special low speed when cooling or heating is not needed for air circulation and infact I can barely hear it running when in this mode. Currently when cooling is needed, the motor ramps up to the cooling speed in a nice progression, and when the temperature is reached, it then throttles back to the air circulation speed. I was also impressed with how much more air is moved when in cooling mode and there is still a good 20 degree drop over the coil. I'll report back during heating season.
I ordered the motor off ebay, and infact it was cheaper then the OEM motor.
This was definitely a good upgrade to my HVAC system.