What I see with experience the basic difference between HC Verma in DC Pandey is that DC Pandey covers the questions which are mostly just like the JEE advanced questions in DC Pandey has very specific questions that are very closely related to JEE advanced but in contrast in case of HC Verma you will see concept based questions and there are many questions which demands hai calculation apart from concept so it will be more time consuming and maybe require a good number of calculations which is not in the case with DC Pandey.