I am thinking of upgrading to Bose AM5 speakers, a Harmon Kardon HK 675 amp and a Harmon Kardon HD 755 CD player.

I have read a lot of mixed reviews re the Bose.

Any guidance/insight is really appreciated.

Bose can have a very distinct sound, and while some people love 'em, there's also quite a few that hate 'em. The AM5s are obviously small and neat but they're not designed to be aimed directly at the listener - they'll fill the room, but many people prefer a more precise image. DO NOT buy them without hearing them first and if possible get a dealer to demo them with your own equipment (bring it to the shop).

I have had the Bose AM15's for 5 years and are very pleased with them. I get a lot of compliments on the sound quality and loudness of the set up.