I've just returned from a trip to Warsaw and stayed in the Westin for the first time so I thought I'd add my general impressions compared to the Sheraton.

Room:-

As mentioned before the Westin rooms (I was in 1501) are definitely smaller than their equivalant in the Sheraton, but not uncomfortably so. Much easier to work in, with a desk that is useable and some extra facilities available (hole punches and the like). My room did have coffee facilities and water. Everything else was virtually the same as the Sheraton (Iron, TV channels etc etc)

Bathroom:-

Being a newer property the Westin definitely scores here with some of the Sheraton facilities feeling older and not looking as impressive. On a more general note I also prefer the seperate shower cubicle as provided in the Westin, but the Sheraton bathrooms are much more generous in size.

Check-In/Check-Out:-

One area where the Sheraton scores. The staff in the Sheraton seem much friendlier and generally more efficient than the Westin. Check-Out yesterday involved a queue of at least 10 minutes even with every customer checking out seemingly haveing some form of problem/query regarding their bill. This may just have been bad luck of course but something didn't seem right.

Restaurant:-

The Lalka at the Sheraton always looks completely dead (6 people in a restaurant with seating for >70) and I've not heard any good things about it from colleagues. The Oriental has a good (if expensive) reputation.

My colleagues report that the food at the Westin is generally better than at the Sheraton. However I've never eaten an evening meal in either the Lalka or the Oriental and can now add Fusion to that list (eat at San Lorenzo's about 500m from the Westin on Jana Pawal II). Others here have said the breakfast at the Westin was much better than the Sheraton. Personally I couldn't see much to differenciate them except that the rolls were smaller in the Westin!!

The bar food in Some Place Else in the Sheraton varies considerably. Some shows a distinct lack of quality in the ingrediants (they had ribs as a special recently, it wasn't great!), but some are quite enjoyable (half decent burger, steaks, fajitas etc).

Bar:-

The Westin bar is a souless affair with a singer warbling away at an annoying volume. Had it been a bit warmer the outside seats may have helped the feeling. Similarly the service seemed slow, uninvolved and generally I was left feeling distinctly underwhelmed. One bar in the Sheraton has much the same feeling (the piano bar) whilst Some Place Else varies between feeling like a cold hotel bar that is trying too hard to be something else and an excellent place to spend an evening. One thing that does help is that the staff in SPE are generally very friendly, something that can make up for many deficiencies.

Others:-

The lifts annoyed me in the Westin far more than they should have! 3 lifts to service 20(?) floors just didn't seem to be adequate. Waiting 5-10 minutes for a lift and then stopping at every other floor on the way down from 15 is one of those annoyances that grows each time it happens.

The general area of the Westin is not as good as the Sheraton which has numerous bars and restaurants within walking distance. Similarly travelling to/from the Westin seemed much more of a hassle with traffic jams around the central train station causing the final 2km to take in excess of 20 minutes in the evening. Again this may just be bad luck but it's something I haven't experienced in the area of the Sheraton.

Overall:-

For no reason that I can put my finger on, given a free choice I would still choose the Sheraton. I think it's mainly a question of staff attitude. Whilst there was nothing wrong with the staff in the Westin the whole place felt cold and impersonal.

If you're on a short visit (1-2 nights) purely for business when you're not expecting much free time then the Westin will probably work for you. But for me, if you're staying longer or for personal reasons/vacation and are therefore likely to have a bit of spare time to either wander the streets of Warsaw or relax in a bar with a drink then the Sheraton would work better.