I have had a very similar experience to you Jubair. I bought my RS 6's on the strength of a demo at Sevenoaks. I spent many hours listening to a variety of speakers and to my ears, the RS6's sounded very nice. Smooth, detailed and taught bass by the bucket load. I eventually ordered a pair of RS6's on line a few weeks later and received them just over a week ago.
My first impressions in my front room were not as expected. They sounded somewhat harsh, with a very hard midrange; not at all like they sounded in the shop. I was dissapointed.
I posted on this forum and got a mixed response. The majority of folks here have suggested a good couple of weeks running in before making any decisions, while a number of people suggested scrapping the RS 6 in favour of the Rega 3's or 5's.
I know these speakers have potential, so I am not giving up on them yet. I am going to let them bed in for a few weeks before making any decisions.
Unfortunately, I am in the process of re-decorating my front room, which has meant old furniture has been removed ready for my nice new sofa's. As my room is substantial size, (5x5m) things are very echoey in there without soft furnishings, so I am unable to evaluate my speakers just yet, anything would sound horrible in there at the moment due to poor acoustics. I have however, left my CD player running most days, so when the new furnishings arrive, I will be able to decide if i am keeping them knowing that they are well run in.
Keep us all posted with developments, as I will.