I have two, which I no longer use... and a dawn lamp, which I still use. I got them all (when I was living in the UK) from Lumie
The reason I stopped using them was that I found the way they had to be used was having a detrimental affect which outweighed the possible benefits.
For light therapy to be effective, your eyes have to be around 20 cm from the light source. They have to be open (i.e. you cannot just lie in bed). You can read, use a PC, do crafts, eat etc... but you have to keep at this 20 cm distance. You are supposed to do this for a minimum of 30 minutes (for the brightest lights) per day, ideally first thing in the morning. I started at that, but it was no good. I was advised to increase it to an hour per day. At the time, I was working as a teacher. This meant I had to get up at 5:30 am so that I could use my light box for an hour before work. I was so tired from getting up so early that I got more and more depressed.
Having said that, I can see that if you were working in an environment where sitting still for 30 minutes to an hour fitted in well with your routine the light therapy would not be a problem. But for me, it was a problem, so I stopped using the lights.
I do still use my 'Bodyclock', bought from the same place. This is a dawn-and-dusk simulator. You set an alarm, the light gradually comes on starting about half an hour before the alarm is due, so that when you wake up your room is already in 'natural' light. My bulb broke a month or so back and I really missed it until I got a replacement.
If you are interested, I do have two 'Brightspark' lightboxes from Lumie. They deliver 10,000 lux at 20 cm. I think I changed the plugs to Swiss ones. The lights are supposed to make a difference in a week or so - I don't know if you would be interested in trying one out with a view to buying it from me? The only issue is I live in Vaud and I see you live in Zurich.
Hope this helps, anyway. The Lumie website is very useful.