I have one I bought at Argos a few years ago and I hate it! It cost about £35 (about 5 years ago) and it's great for stitching by - I was doing a lot of cross-stitching at the time! It's one that you can move around easily, but I've never thought much of it. Bright as heck, with I think 2 lower settings. But if I was going to buy another one I'd definitely go for a bit pricier, or just go for the blue coloured daylight bulbs in whichever places I was most likely to be. They look sort of tinged blue but don't shine blue, they're very bright! Make sure to get out as often as possible in daylight, or at least sit by a good window as much as possible even if you buy a SAD lamp! Also, you can buy ones with alarms so that you wake up to graduating daylight as the lamp gets brighter and brighter!! Mine doesn't make much difference to me, IMHO, but it seems to cheer others up! Lol
I have been using one for a few years now. I use it for 45 minutes each morning and if I'm feeling bad then a top up around 5pm for upto 30 minutes. It does make a tremendous difference to my mood. I wouldn't be without it. I use it from November until April.