1. Description of a product that's currently advertised in Stereophile: obviously pandering
2. Description of a product that used to be advertised in Stereophile: an attempt to get them to advertise again
3. Description of a product that has never been advertised in Stereophile: encouragement to get them to advertise
4. A product currently advertised in Stereophile is not mentioned: an attempt to get them to advertise more, in order to get coverage
Covers all the bases, eh! And you should read Bob's classic essay on how to write a "Manufacturer's Comment" letter: www.stereophile.com/features/22.