Originally Posted by santoshk121
We are kind of considering NaviSite for their presence in India and wanted your opinion about them.
Hi santoshk121, welcome to the site.
It sounds like you have somewhat already made the choice toward NaviSite. I'd say both of your choices are solid. Both Rackspace and NaviSite are publicly traded companies, which means they are profitable and sustainable (something that is difficult to verify/guess when you come across a company you've never seen and/or heard of before).
As far as NaviSite reviews, while I do not have direct experience with them, I would suggest searching for them online "navisite reviews" on Google or popular web hosting forums. However, I think the biggest test of validity and service is the fact they are a public firm. This should provide enough comfort that they are not out there just to steal your money and disappear.