Whether to file RCR or divorce is a very important question and the answer lies on the basis of the facts available with you and your future desires. RCR is not a stepping stone to obtain divorce, as some popular belief goes. If you want to cohabit, go for RCR and if you want divorce, then go for divorce.
The time takes in both the cases is same. In Delhi, if any one of the party along with his advocate pusues the matter with sincerity, it will take two and half to 3 years. This period varies, if one of the party evades to receive summons or one of the parties is outside India etc.
You can have further discussion in this matter in my chamber, as you are in Delhi by taking prior appointment on my e-mail address: