If you want the harbourview, go for the IC. If you want slightly better access to upscale shops, go for the Shang. I find the rooms and service at each to be roughly equivalent (though when I stayed at the Shang there was no club); I did find the Shang's elevator service to be frustratingly slow.

Club access in the IC gets you not only drinks, but exceptional appetizers in the evening (had lobster, duck, foie gras, etc there in November). Breakfast in the IC Club is very, very good with high-quality stuff (Western and Eastern). Breakfast at the Shang is in their terrific Cafe Too, and it is an enormous, very good quality buffet. The Shang's breakfast has far more offerings than does the IC Club, though I'd give the IC the edge on quality.

The IC also has a terrific spa, which your beloved would almost surely enjoy.

I also agree with others about prices. If you haven't done so, you might try e-mailing the hotel directly, perhaps letting them know you're looking for a harbour-view room w/club access, and asking if they have any packages to offer.