If you're not expecting to work by it, it might be okay. My neighbour got one and was very disappointed - I think he expected the same sort of effect as a 500W halogen lamp! Instead, the brightness of three lamps is just enough to light the path around the side of his house so he can see where he's going.
Also not sure if you care about the warmth of the colour, but most solar lights I've seen produce what IMO is a fairly unappealing white-coloured light, rather than the more yellowish colour of mains outdoor lights.
Edit: just realised this is for working in a shed, not outside one - just ignore my colour comments...
I've got one I bought from Makro, it has 5 LED bulbs behind a diffuser.
My shed is about the size of a single garage (about 10ft x 18 ft inside), and I could probably do with 2 lights.
However, I only have one, in the middle of one of the long sides against the wall, so it probably isn't positioned the best either.
It's nowhere near bright enough to work by, but if I'm just looking for a particular toolbox, or I'm padlocking the bikes, then it's fine. However, If I need to rummage inside a tool box to find something small & indistinguishable, i.e. a particular size allen key, it could do with being brighter.
Hi. I just wanted to say that I have found the little 'led' type shed lights to be pretty dull, not really that useful. If you are confident in connecting a lamp to a 12v car battery with crocodile clips, you can use a regular domestic lamp fitting with one of the new breed of 12v dc fluorescent lamps and have equivalent to a 60 watt bulb using just 11w - of course, there are some smaller or larger options but the 11w suits most shed or small workshop type applications perfectly.