Was debating the same question. While business usually takes me to CP South, for leisure purposes I used to stay at the IC over the previous years. Always a good option to use the BOGO voucher, plus good upgrades and benefits as RA.

For my most recent (and somehow short notice) visit to Amsterdam the IC was way beyond EUR 500 and n/a on points. Thus I gave the Kimpton a try. Booked a comparably high rate around EUR 250. My expectations were set by Indigo standards. Kimpton exceeded them by far! Superb staff (even though the hotel was sold out), generous suite upgrade, great atmosphere in all public areas. The style and decor of the hotel is top notch, as is the quality of all materials and furnishing (which is largely different from Indigo, which always reminds me of IKEA).

Overall, I was most positively surpised by the Kimpton. Absolutely nothing to complain about. Clear recommendation! Also, as previously mentioned, location is more convenient compared to the IC if you want to visit restaurants/bars.