Depends what you want from your time in India but (of the bikes you can get out here) I'd recommend a Pulsar (made by Bajaj)...
I've only pottered around south India, but it seems that:
- Pulsars and Bajaj are fairly common (good for parts, if needed...Bajaj showrooms in every town)
- mine has been very reliable (4 months now, and all ok - touch wood!),
- at 150cc, they're as fast as you want to go (sitting at 70-80km/h is fine)
- mine was 3 years old and cost me 400 quid
[- and the vast majority of the other bikes out here are 100cc work-horses]
Whereas, in the past four months I've only seen about 6 Karizmas (and all have been parked) and of the handful of Westerners i've talked to with Enfields, everyone has experienced mechanical problems...
Like i say, it depends on what you want from your time in India...what price 70cc of extra (possibly mechanically suspect) kudos and rarity value?