Since you Indians already bought 4 209s from HDW you have now the possibility to change them into the super-silent and therefore most effective subs of your fleet.
Nevertheless I would prefer to sail in the larger 212 or in a Kilo since the 209 is for sure among the most cramped ships you can think of. The crew is packed like sardines in a can. Only the 206 class is even more narrow.
:-)
The Kilo is no better when it comes to comfort(it's Russian after all!!).It's got a much larger crew of 50 or so,which itself negates any advantage in space & most models barring recent ones have poor climate controls,which means that operating in places like the Arabian Sea is like staying in an Oven.The Type-209s are better in that regard.