I went back and forth here, between four and five stars. For the things that really matter to me, this new hotel (we were there in August 2011, when the hotel had just recently opened) gets five stars. It was perfectly quiet. We were on the top floor, and it was so quiet that I assumed that none of the rooms around us were occupied, but noticed the next day that they were being cleaned; so the sound proofing is first rate. The hotel is in a beautiful old renovated building. On the top floor--nice because you have no one above you--the room was small (eaves cutting in), but fine for us. Everything was in perfect shape at that point. The decor and style is quite contemporary, interesting in contrast to the older exterior. I ended up giving the hotel four stars instead of five because some people would find the room size a problem. The King bed was lovely, but there wasn't space for much else in the room, and the shower space (under the eaves) was so tight that you had to step out into the room itself to dry off (and I'm small). As others have noted, the toilet room, on the other side of the room from the shower, has a frosted glass door that doesn't reach all the way to the floor, so you would want to share this room with someone you know well. Because the designers used the space as they found it, the counter and sink area, extending from the shower under the low eaves, was huge: plenty of room for everything for a change. All in all, we were very happy here, and wouldn't hesitate to return. (Yes, the internet connection was slow.) A tip: if you have a car, the parking is extremely expensive . You park outside at the metered parking. We learned from someone who lived in the city that--if you are able to walk--across the river along Haldenstrasse going toward the Transport Museum are public parking lots used by residents and visitors to the downtown area. There is one right past the Grand Hotel Europe. There you can leave your car overnight, and for limited hours during the day, and all day on the weekend for free. It's absolutely safe--it's the parking area for the people who live in the area as well, and it will save you a bundle.

Lucern is a wonderful city to visit, either in summer or winter time. The Renaissance hotel is a very good option, and can be obtained at a relatively good price if booked in advanced. It is a modern hotel which is fully equiped. There is a bar and a restaurant on the main floor...usually packed at night (dont worry, you are not bothered by the noise). On top of that, we have been upgraded at arrival on the hotel.
Having said that I will now number the pros and cons:
PROS:
-Location: Near the train station (3-5 minutes by foot), KKL museum, lake and other main attractions.
-Rooms: Spacious and well illuminated rooms with king and queen size beds. Huge showers. Clean.
-Staff: Very kind and helpful staff
-Front desk employees are very polite
-Extra services: Free wireless connection on demand
CONS:
-Rooms: The thing that disturbed me the most was the fact that there is a glass wall separating the toilet/bathroom and the bed. So whenever you feel like doing #2... well.... your partner is able to see the entire process...
-Breakfast is "OK", nothing out of the extraordinary, quite abundant
-Rooms are fully equiped, however they do not provide the basic bathroom kits such as showercaps (which are very useful in my opinion), unless you ask for them on the front desk.
All in all, I would recommend this hotel.

An excellent hotel to stay while in Lucerne. Staff are just great, very helpful and professional in everyway. The hotel is very well located. I do recommend this hotel with no hesitation.

We stayed in August 2011, when the hotel was still very new and we managed to get a good price deal (by Swiss standards).
It is very close to the station, and as Luzern serves as a "base" for most people for travel in the region, it serves the purpose well. Having said that, the room itself was pretty good and though not very large (but completely standard for Eurpoean standards) was extremely well designed utilising space effectively.
The lovely ladies at the reception are very efficient, and helpful. The room service food is of very high quality (better than the "touristy" food that most restaurants in Luzern serve) but the menu is somewhat limited.
Con: the only thing I can complain about is the complimentary internet connection which was a pain to connect to and I had to bother the ladies at the reception a number of times to get a new login and password.
Other than the above, a minor complain is that the 4th floor (or was it the 3rd?) where we were staying had steps in them which was a trouble when carrying our baby in a stroller.