Am a regular in Berlin, but first time staying at this landmark hotel. Of course, this is the "new" Adlon - the original pre-war hotel survived the war but was burnt down shortly thereafter by the Red Army (by mistake, apparently). This reconstruction dating from 1997 however retains a lot of old-world charm, and rather gives the impression, from the floors to the common areas to the interior decoration of the lifts, as a new renovation of the original property rather than a complete reconstruction.
There are better bargains to be had in Berlin, and whilst the location is amazing in terms of embassys, the Brandenburg Gate and the Bundestag, it's actually pretty terrible if you just want to take a walk in the evening to find a restaurant. As any real Berliner will tell you, this is actually one of the deadest spots in town.
That said, this is the place where "everyone", from the Clintons to Obama to Bono and Michael Jackson stay(ed) when in Berlin. And the taxi fare to nearby spots with more "action" isn't an issue if you can able to stay here.