As an SPG Platinum who is also a referred Royal Ambassador , I mostly agree with your sentiments. I have probably 7-8 IC stays this year, trying them out. After 2-3 of those stays, I had already concluded I was sticking with SPG going forward.

The important reasons:

1) Far fewer choices. If the IC is booked in a particular city, you are out of luck. Forced availability in both programs is exhorbitantly (generally unjustifiably) expensive.

2) Poor value. I have made it a practice to check IC pricing first every time I stay in a city with an IC. 90% of the time I can find a nicer Starwood in that same city for the same or less (e.g. St. Regis in SF vs. Mark Hopkins), or a slightly worse SPG property for much less money. Relative to SPG, IC properties are consistently overpriced.

3) Inconsistent product. ICs are all over the map in quality. Dallas and Austin are bad, basically like a nice Sheraton at best, for twice the price (I am not a fan of most Sheratons, either; they are, in my experience, by far the most inconsistent SPG product).

4) Agree with the comments about the beds. SPG beds (and showers), particularly in Westins and Ws, are much better.

5) Better loyalty program overall at SPG. IC awards are capacity controlled, and there is no credit card available.

6) Inconsistent service at IC, on average not commensurate with the prices (agree with you on this one).

In IC's favor, there are a few points:

1) Free minibar is nice. Though for me, most of the time I just want the bottled water, which I get for free about 50% of the time at SPG properties. This is not worth very much to me (though I can see how others would value it more).

2) The Ambassador amenity (fruit and water) is much much better than anything SPG offers. It is also delivered pretty consistently, usually waiting in my room (I think your experience in this respect was a bit of an anomaly). The SPG equivalents are unappealing (to me at least) -- bad beer and pretzels? Yuk. I take the points, but much prefer the fruit.

3) IC LA is much nicer than any SPG LA property I have been to (I will continue to stay there because I don't like any of the Starwoods; for such a big market, SPG has really lousy properties).

4) Free movie at IC is also nice. No equivalent at SPG.

5) IC upgrades are marginally better and more consistent than SPG (suites maybe 50% of the time at IC vs. 20% for me at SPG, 2 category the rest of the time vs. 1 category usually at SPG).

Overall there is not nearly enough of a difference in the product to justify the price differences.

I am also Platinum at Fairmont, BTW, and would say many of the same things I said about IC about their program (much worse program overall, inconsistent product though better than IC, benefits offered inconsistently -- amenity not provided without asking at least 30% of the time, beds worse than SPG, fewer properties, and, most importantly for me, zero upgrades except for 4 a year which require you to use coupons -- they strongly encourage hotels *not* to upgrade elites to "provide consistency" -- I have complained about the policy and this was the explanation).