We stayed at Leonardo for 3 very cold nights in winter. We had booked a double room through an agency and we were instead given a twin bedroom with the beds joined together. When I called reception they said that they were fully booked and could only change it the next day - of course there was no mention of this during check-in.
The rooms were too hot, they clearly have a problem with their heating - if you set the temperature at 21 degrees, it heats up the room to well over 24+ degrees and then you actually have to open the windows to regulate the temperature. Additionally, the rooms were quite small.
The customer service wasn't the best - the staff were generally quite gruff. They don't really give you any help with local tourist information, so you're pretty much on your own.
The only positive was that the breakfast spread was one of the best I've seen. I have stayed at a range of star hotels but they really had a great hot breakfast at Leonardo and the service here was quite prompt.
Last but not the least, the Wi-fi service here is a total rip-off. If they think customers will pay 12 Euros per day for internet, they must be delusional. Definitely a big issue.

Very convenient hotel in Berlin. Specially given the good location and connectivity to metro rail.
Overall staff attitude and a grand resturaunt makes it a good experience.
The room size is however small and you need to pay for wi-fi connectivity.
But Internet and printer facility in the lobby covers it up.
All in all very good hotel and a great stay.

My husband and I arrived from the airport to the hotel before check-in time, but the staff at the hotel swiftly and happily let us check in early. The room was small but nice and the breakfast was convenient and had a lots of choices on the buffet. The maid service was exceptional and the tiny bar downstairs was convenient and the bartender friendly and knowledgeable.
Location was great. Everything we needed was within reach via bus, walking, etc. One of the best things we discovered was that direct across the street from the Leonardo were two outstanding restaurants, the Trattoria la Pignata and theGalerie Violin Restaurant, both delightful!

The Hotel, in the center of west Berlin. Rooms are quiet and the breakfast is very rich and tasty