Product review (2 stars): Proper fit and functional, but sticks open
I purchased this in January 2012 to replace the original solenoid that was part of the original installation (around 1997).  The original part had begun to leak and I figured it would be a cheap fix.

The part came and fit properly.  It didn't leak and seemed to work just fine for the rest of the heating season.  Sometime during the next winter, I noticed that even when the furnace wasn't running that the valve was open and allowing water to flow.  If I tapped it with a screwdriver, it would click and close.  This became and frequent, recurring issue.  I'm not sure if it was the particular brand or just a defective valve (at least one other review cited the same issue), but I'm going to try to get one from a different manufacturer.