Just back from a stay at the Hilton, with mostly good things to say about the stay. Our rate was very good having booked the 'January sale' offer, back in well, January(!).
The staff we encountered were generally very friendly so big thumbs up for that. The breakfasts were excellent, included in our room rate, so very good value. It's a massive area they use for breakfast but there are loads of staff buzzing about keeping everything running smoothly. We also used Cloud 9, the bar on the top of the hotel. Unfortunately the terrace wasn't open, the reason being the chance of rain, despite that seeming fairly unlikely. Anyhow, spent an enjoyable couple of hours in the lovely comfy chairs by the window, again good service from the guys in the bar.
The rooms are a great size, no doubt but agree with a previous poster that they are a little dated.
My main grumbles would be the small old TV in the corner of the room - come on get some flat screens in!
The biggest bugbear though in a so called luxury hotel - a sub standard shower. Really low pressure, a 5 star should have a rainforest shower without doubt. Towels could be a little better quality as well.
We found the location of the hotel pretty good, could stroll along the river to town, or more directly it was about 15 minutes walk to the Opera House, or a couple of metro stops into town.
Would stay here again if we got as good a rate as this time, but if money was no object, would have to be the Aria in Mala Strana.