Gardiner sill brush is great.
problem with vikan hi lo is its very easy to scratch the sill with the headstock as you are cleaning the bottom of the window. if this is the case, and it was the case with us until we spotted what was happening) you need to adjust your technique to stop short of the sill as you clean the bottom frame. however, on the superlite Gardiner sil brush the head stock is a lot smaller so you are far less likely to do so. what is more, the Gardiner brush is so light, that even if you do touch the sill with the stock, you are far less likely to damage it.