Stayed here for 2 nights for business, and had a nice experience! Enjoyed the room, with open view on shower and wall mirror. However, described as design hotel is just all new types of bathrooms. No free wifi, but nice breakfast and good location in business centre of dusseldorf.

Recently stayed here, after finding that there were no hotels at all available in Cologne (where my trade show was happening). FWIW, the commute was not too bad: a 15 Euro cab ride to the Central Station, and a typically easy German inter-city rail journey. I feared that the hotel would be sub-standard, but I needn't have worried.

Check-in: nice new lobby. Efficient and friendly front desk personnel. One BIG complaint: Wi-fi only available as a T-Mobile voucher: 10 hours for 19.95 Euros. This should really be free and I am docking the hotel one star for this. I was informed that breakfast would be half-price EUR 9.50 instead of 19) if I joined the Melia hotel club. I did this and received the discount as well as 10% off all meals. More on this later.

ROOM: I was in the larger Resident Suite. King-size bed, desk, recliner, flat-screen TV. Mattress a bit too firm, but bed was nice. Others have mentioned the werid/trendy/design-y shower in the middle of the room. um, ok,,,but I would have preferred a bath. The shower was lovely, though. One note: I had a smoking room, and if you are one of the few smokers left in the world, you will appreciate it. It was not horribly charred and smokey inside. A complimentary mini-bar, which had 2 waters, one juice, and one coca-cola replaced daily. Nice that it was free...is it churlish of me to wish for a single beer, as well?

By the way, for those staying longer, there was a microwave, mini fridge, and a tea-kettle with some tea and coffee fixings. Nespresso machine would have been a better amenity, and whatever you do, do NOT make the mistake of drinking the provided instant cappucino mix. It was truly disgusting.

Much better was the breakfast, which had every conceivable thing: 2 kinds of smoked salmon, a wide variety of meats and cheeses, delicious freshly baked pastries and breads, fantastic fruit assortments, yogurt, and even a fresh orange juice squeezer. The coffee could have been stronger, but all in all a dynamite breakfast.

Best thing about Innside: the restaurant. I was working all day in Cologne and too tired to even think about exploring. Luckily, I had read some positive reviews of the restaurant and was not disappointed. I ate all my dinners at the bar, and was attended too in a fantastic way by Davit: an excellent bartender and really nice guy. His recommendations were spot on, especially the lamb chops, filet, and the mixed salad with shrimp and goat cheese canneloni. Also, they feature a cheese assortment: 9 varieties of cheese for EUR 12. Delicious. I also had a lobster bisque, a filet steak, and some other dishes. Everything was perfectly prepared, with innovative garnishes and sauces, and MUCH better than I had any reason to expect.

All in all, I was very pleased with my stay, and would not hesitate to recommend it to other business travelers.

Stayed in the Innside Seestern for 3 nights for a business trip.
Check-in was hassel free and quick. The "open plan bathroom" was refreshingly different and gave the room a bigger and lighter feel. The bed was very big and comfy.
Breakfast was plenty full. I really liked the loose tea and the "fresh orange juiceing".
However if you booked without breakfast there is a backery very close by.
The gym is rather on the small side and too warm from the nearby jaccuzi.
Instead I went jogging to the nearby (2.2km) outdoor swimming pool in Loerick which opens at 6am and has a 50m pool.
Dinner is a rather small menue but quite tasty.

Surprising architecture, but very quit, modern and clean hotel. Staff very helpfull. Room was surprising with the open shower in the middle. Breakfast was great and our evening dinnenrin the hotel restaurant superb. Highly recommended. Only - point : out of the city centre, and the U Bahn is closed very early. You need a own car or pay a lot of money for cabs ( city centre 15 Euros)