I would say that you need to be more specific about the power you need vs. the weight of the screwdriver. Are you looking for a very light screwdriver with limited power, or a heavyweight, powerful unit?
Do you need any extra capabilities like hammer drilling or impact driving?
I use the de-walt gyroscopic convertable unit, since found the non-convertable/fixed unit and wish I had that instead as mainly use it straight and the fixed unit would have no 'wobble' in the handle like the convertable, is also smaller.. that said I use the dewalt alot and really like it, sadly being in Aus I had to import it (from germany) but you can get it in the uk... also had a look at the bosch blue unit avail for the $60us mark, looks ok but cant swap out the batteries like the dewalt. Would like to give it a try to sample a 'non gyroscopic' style unit.. maybe one day!