The Ritz Carlton is in a god-forsaken place, you have to drive out of there. It's also the ugliest structure on the Bosphorus. Forget the Marriott on the Asian side, it's not even a Marriott run hotel, it's a franchise and it's deep in the asian side overlooking the meatmarket. The Hilton in Harbiye, Taksim is an old and refurbished hotel but has the best location and views. Among the three you mentioned, I would choose Hilton Harbiye (close to Taksim, the Times Square of Istanbul.)

If you definitely prefer the chains, then I'd say prefer the Swiss Hotel. The Grand Hyatt is a newer hotel, although it doesn't have the views of the Hilton or the Swiss. The Four Seasons has a fantastic location on the Boshoprus.

My choice would be 1. Swiss 2. Four Seasons 3. Hilton 3. Grand Hyatt.

I agree with choice of the Istanbul Hilton among the Hilton group hotels.

The Ritz is not in a god-forsaken place, but on a hill and not within easy walking distance of any shops, entertainment and restaurants except Topaz restaurant, Tiyatro Cafe (in G-Mall) and Dolmabahce Palace. In fact it is no different than the Swiss Hotel in terms of proximity and requiring either a longish walk or a short taxi ride to get anywhere.
Its rooms are rather too traditional and ornate but smaller than the Hilton's,

As Medbird says, forget any other Marriotts. A small and cheaper Hilton, the ParkSa, is a decent hotel and reasonable value. The Hilton Garden Inn at Moda on the Asian Side may be an interesting choice for a second or third visit to Istanbul. It also gives the advantage of reaching the historic town by historic tram and ferry without hitting heavy traffic.

Consider staying in a Turkish boutique hotel. Much more interesting than a chain and some have similar services. I think the chain hotels are boring.

Agree with mes2525. I'd suggest you check out this site, their reviews are very reliable.
http://www.kucukvebutikoteller.com/eng/Default.aspx

Thanks for the responses. We do need to stick with Marriott/Hilton for the free nights with points. I had read that the Ritz Carlton is kind of out of the way. Think we'll stick with the HIlton, although I read it has an attached conference center with a huge parking lot you must cross to get to the entrance to the hotel.

The Parking lot in front of the Hilton is underground and the building is about a 300 feet walk from the main street either to your left as directly across the doors through a reasonably well landscaped area, If you go to the right after the Hilton convention center, you come to the "Convention Alley" which is mostly concrete and with a large parking lot but is also a short cut to the upscale district of Nisantasi-Tesvikiye with its lovely cafes, restaurants, bars and shops.

Currently access to both the Hilton and the Ritz is rather difficult and time consuming because of major construction in and around taksim Square where the municipality is busy building dive tunnels for traffic and preparing the park grounds for a replica of an old military barracks by cutting 600 oak and plane trees in one of the few green areas in the district.

the dive tunnels shoyuld be finished by the time you arrive so the traffic will be somewhat better but you will be walking by concrete lined narrow pedestrian walkways part of the way rather than a boulevard with beautiful old trees.

We have been protesting this project as inhabitants of the district together with the Association of Architects and Engineers, all neighborhood associations and some political parties to no avail.

Cobbie2, that's not right. there are two entrances to the hotel, and the main entrance from Harbiye is totally intact; and that's the one you would be using anyway to get to the hotel. Between the bleak house that is the Ritz and the Hilton; the Hilton is a no brainer.

Medbird, I live in the area, only half a mile from both hotels and I am not in a wheel chair.

The entrances to both the Hilton and the Ritz are totally intact. The problem appears when the taxi tries to drive you to either hotel or when you try to walk from the Hilton to Taksim square or thereabouts. My life has passed around Istanbul Hilton since 1956 when it was built not only because I always lived nearby, stayed there a number of times, attended numerous receptions and organized some there but because I was the RM consultant of the Hilton group in Turkey for almost ten years. The same is true for the Ritz where I was also the RM consultant of the property owner and the contractor from the day the "ugly" building started to be built.

Just yesterday it took us all of two hours to drive from Nisantasi to our house near Taksim in addition to the 45 minutes we spent to have a drink at the Ritz when we stood still in our car just at the entrance for ten minutes and decided that we should give the car to the valet and may as well go in to have some wine.

Don't stay in a chain hotel in Istanbul...there are wonderful boutique hotels within walking distance of everything you want to see and do. We've stayed twice at the Rose Garden Suites...wonderful hosts, beautiful rooms, a van to take you to restaurants, etc.

Thanks for the boutique hotel info, however, we will stay with hotel points so as to save money. Most likely stay at Istanbul Hilton