The Interconti club is pretty good in my opinion. Reasonable prices, hot food for dinner ( only mo-fr / not on the weekend ) good service. Very nice pool / Spa area ( even better for a city hotel )
Next stations are U-Bahn Wittenbergplatz oder Bahnhof Zoologischer Garten. F
Wittenbergplatz I would say is a walk maybe 8-10minutes.. Zoologischer Garten 2-3 minutes more. Check before where u are heading to so you know which trainstation is more convenient for you.( For sight seeing Zoologischer garten as well as Potsdamerplatz are very central located )

Rooms in the west tower are more recently refurbished.

Palace is very similar Location couple minutes closer to transportation.
Nerver actually used their clublounge but stayed a couple times in ther club rooms / suites ( suites = one big/huge room so no real two room suite)
Often bookable with VERY reasonable rates. Decor is pretty dark as well ( black stone walls) You better check the style on their homepage

The Hyatt is located at the PotsdamerPlatz (next to..) so you have a maybe 3minute walk to S / U-Bahn. Clublounge is a little smaller than IC. I would rate the IC club above the hyatt ( in all terms..but Hyatt still being a good clublounge)
On the hotel homepages you should get a pretty good idea of their room/overall styles

Regarding price you have to check with your specific dates. ( For example Sat May 30th the final of the German soccer cup takes place... Saturday june 6th the championsleague final will take place at the Olympiastadium, which is the biggest soccer event of the year.Also expect to have tons of drunk soccer fans in town if you are there on one of the dates)
Hope this could help a little