Longer and faster, better?

[mackguyver]

Since you are in India, buying a refurb from Canon is not possible.

True, unless he has a US buyer, but he should be able to buy from Adorama. The have a 400 and 500 Mk II right now at excellent prices - I'm sure a 300 will pop up at some point, too:
http://www.adorama.com/searchsite/default.aspx?searchinfo=canon+refurbished&sort=p_price_sort|1

 

[Deleted member 91053]

I frequently use my Canon 300mm F2.8 L IS Mk1 with the 2 x Mk3 (not Mk2) extender and get very good results if the light is good. No it is not as good as my 600 F4 L IS (now sold to pay for 800mm) but it is not that far short in good light and weighs/costs a LOT less! Camera is a 1D4.