My perspective on Thailand
Hi there,
Hope this helps,...I have no experience of the IC Bali, but do have pretty extensive experience of HI Phuket and Phi Phi Island, having stayed at both properties in a variety of rooms on many occasions (including my own honeymoon).
For my wife and I, the HI PhiPhi is an hotel which we shall always continue to revisit - thoroughly recommended. The HI Phuket, whilst located in Patong (certainly an acquired taste) doesn't necessarily require you to spend a great deal of time in Patong itself. If you *do* decide on the Thailand route, then I would strongly recommend booking a room in the Bukasorn (spelling?) wing, as it is more of an oasis of calm from Patong than the main wing - if Patong isn't to your taste then you never need leave the hotel! Plat status has secured me upgrades here without fail, last visit being poolside villa with complimentary wine/fruit/cocktails. Highly recommended.
PhiPhi island HI is lovely - try to book a water front bungalow, although your Plat status ought to secure you an upgrade to water front (the heirachy goes Garden View, Sea View, Water Front). Quiet, isolated and away from the backpacker element which is crawling round the main town.
Another tip you may not have thought about, but within the IC family, is the Crowne Plaza Karon Beach - the advantage here is that you're a fair way away from Patong if that's not your cup of tea, but Karon is pretty sterile (all the more reason to stay in your room, as per the honeymoon theme!) - again Plat status secured me a room upgrade here to a rooftop villa with plunge pool etc. Highly recommended.
Once again, not having visited the IC Bali I can't offer opinion on it, but I'm sure whichever country you choose you'll have a great time. I can pretty safely say that all the IC hotels I've stayed at in Thailand have recognised my Plat status, which is more than can be said from my UK/EU experience!
Any queries please don't hesitate to drop me a line.
Nick