I find it very interesting as I get suite upgrades at CYs far more often than any other Marriott brand. While I tend to prefer FS hotels which have lounges, the one thing I really like about CYs are their King Suites. I almost always get an upgrade to a King suite (though in fairness I almost always have to ask for it as well.) But I can't remember the last time I asked for a suite upgrade and I didn't get it (assuming they had suites available of course.) I really like that they have a separate temp control for each room. It lets me crank down the temp in the bedroom while leaving the living room area comfortable.

And as for the restaurant, I guess that isn't as much of an issue for me as I very rarely eat at a hotel restaurant. They tend to be expensive and quite often not that good. So I don't tend to have that extra "tax" you have.

I will agree that HGIs have a much better breakfast (and I guess the restaurant though I've never eaten anything other than breakfast at one.) But I've never (even with about 4 years as a Diamond) been upgraded to a two room suite at an HGI. They've upgraded me to a Jr suite, which has more room, but doesn't provide that temperature separation a true 2-room suite allows. When I was travelling to Overland Park monthly for a few years, I could choose the CY next to the Sheraton conference center or the HGI right next to it. Other than for a bit while the CY was being renovated, I usually would go with the CY over the HGI because I'd almost always get a suite. Note that as a business traveler my meals were paid for, so free breakfast and an HGI having a restaurant wasn't really a big deal to me. There were lots of other "better" breakfast/lunch/dinner places I tended to hit than the hotel restaurant.