I wish I could give you an answer about the timeframes, but that one I am not sure about. I believe you can check timelines through this site and compare. We are doing DCF, and that has been extremely fast - partially at least becaus Chennai is FAST.
You may have heard all this before, but the CR1 allows your spouse freedom to work immediately, costs a lot less overall (if you do K3, they will have to go through AOS - which can be a long time and costs $1010), and in some states, you can't even get a driver's license unless you have a green card/immigrant status - which a K3 is technically not. Those were all things we took into consideration when choosing which path to take - the ability to work, drive, etc. are critical to a smoother, less isolated transition to the US.
Many people have said that the time difference between the K3 and CR1 are fairly negligible, and with a CR1, you don't have to go through yet another round of papers and interviews! Something to think about!

Good luck!