Well its very subjective , if you have clarity of concepts very well and you need to practice more to get a strong grip on the subject then go for a das gupta, but if you want to build concepts and practise along with it go for rd sharma as it has lot of solved examples but its not alone sufficient if you require it for jee , after rd then go for a das gupta.A das gupta is definitely better for jee standards(if you are preparing for it)