As you probably know, .IN is the new country code (ccTLD) for INDIA, which has one of the fastest growing Internet populations in the world. The .IN namespace is still in the newborn, or toddler stage, just beginning to get established. Like .DE and .US before it, some people are getting in early, and some people just overlook it. I believe that a couple years from now, the people that overlooked it will be wishing they had the vision to see it coming.
That's just my opinion, of course, and I personally like the Indian namespace. For that matter I'm a fan of country codes in general, so long as it's a major country with large population. I've sold a few nice .IN's for $XXX, hade a couple $X,XXX offers on my best ones. Nothing too spectacular, but a good sign this early in the lifecycle.
As for 3-letter .IN's, I've got a few that get decent type-in traffic because they are acronyms for established Indian companies. Whenever I've registered my 3-letter .IN names, I went to Google.co.in and checked to see what kind of results they got. It's not a full poof system, but if you take the time to examine the search results, you can get an idea of how many Indian companies or entities use the same initials/acronym.
There is no guarantee, but I think the future is bright, and plan to hold mine for a while.