Each to his or her own.

I am frequenting the Hilton Berlin for more than 10 years now, 2-3x/year with stays of 3 nights on average with the exception of a 12 nights' and a 8 nights' stay. Over the years I was Blue, Silver, Gold and now Diamond. Those Diamond perks have been reduced all over Europe (as far as I can judge) as have the offerings in the ELs. However, the Hilton Berlin is doing fine customer service like. The ground floor EL lacks the views, is less cosy than the former one, but it is spacious. For breakfast the EL atmosphere is quieter while seating has improved considerably agter the first floor restaurant refurbishment. The cuisine in the restaurant Mark Brandenburg improved, too.

When the Hampton by Hilton opened I have stayed there 2x6 nights first, the followed by occasional stays. Of course, it is more basic, breakfast is there but nothing to write back home at all. The hotel is in a very good condition, well maintained, and I do like the top floor balcony rooms (those I have stayed in and will stay in in future time). Locationwise I like it much better than the Hilton (which is in a more museum like neighbourhood plus very touristy although impressive and beautiful), since is is in a genuine resident area.

Now, when the acclaimed Waldorf-Astoria Berlin has been opened I had to give it a try. Oh yes, the rooms are top notch, many staff is very accomodating, but we were let down by the fact that our room we were shown to (King room view view), was out of air condition and therefore over heated (plus 30 degrees Celsius) with no air condition going on at all!. Subsequently they tried to downgrade us into a standard room and eventually and seemingly reluctantly they gave us a King Junior Suite with view. The whole procedure took one full hour involving waiting in the lobby for the employee talking to his supervisors until one of them accompanied us to the 'library' to wait there instead. (I complained on the spot and I gave a written feedback after check-out, but this is another story that would go beyond the scope of this thread).

Guest preferences are individual, glitches and mishaps happen in every hotel but then it is the hotel to do its best to accomodate the guest. Back to the Hilton Berlin: it is no exception to the rule but it often does an excellent job, mainly a really good one. That is why I like to stay there.
(And certainly, Gold and Diamond benefits add to this. Free full breakfast in the Hilton Berlin, NO free breakfast in any WA.)