Product review (5 stars): Stop looking...buy this one...
Fits like a glove in my custom built hood.  Quality is that of $500-600 units I saw at local home stores.  Favorite thing about this unit is it has no extra parts of details that do not add to its functionality.  'Squirrel cage' type blower fan literally runs circles around the 'fan blade' type blowers in Home Depot/Lowes style hoods.  Motor housing is solid cast metal and the unit is very simple on the inside.

Installed quickly since you can screw straight through the front or back wall of the unit to a 2x4 you place in the front and back of it.

Very quiet for its power.  Clears my kitchen of an entire 20" cast iron skillet of bacon with ease!

Replacement of this unit would also be easy due to its design.

I thought the color would bother me not being stainless, but it is so slim and hidden (maybe only 3/8" reveal below mounting surface) I can not see the unit to know its not a different color.  I will not be messing with it since it works so well.

I also originally purchased the Broan LT30 30N T-Shape Hood Liner for PM250 and PM390, Silver, 30-Inch Silver, but was able to build my own opening for it out of simple 2x4's and finish grade 3/4" plywood and paint the mounting surface with high gloss white to resist oil saturation.  Works awesome and is easy to clean.

I likey...