Mr Subman,
Its very bad to cut down on the amount of light you are letting through BUT you get what you pay for. If you are trying filters to see which ones you will use then the GS ones are good for a trial but if you find you use them a lot then get a good one of that colour.
Some people swear by the colour filters for planets but I find I mainly use the 80A light blue more than any and then only very rarely. If you think about it then the blue one will work on Jupiter and Mars which are both basically reddish as they will increase the contrast (because blue is the opposite to red in the colour wheel), the others will have very specialist tasks but the light blue will work most times if you need a colour filter on a planet.
Good luck
