at least for usage on mobile its great to see airtel offering cheapest option of 250 for 1 gb. though smartbytes is still not valid for rajasthan but what i read is they intend to inform you when you approach your limit through sms. and any which ways you dont need unlimited plans for mobiles. your wifi , mifi & broadband is for that kind of usage on pc.
i have already covered in another thread that use Onavo count - free anddroid app on mobile & tab to keep check & notification about your usage, if any app is hogging your net, you can fully control your data usage.
The world would be a better place to be in if we could have just one flat plan basis day, week or month and not volume. Which plan to choose, how much have I used already, how much more before I shall be charged and at what rate??? So much to get 3G running on my phone or tablet. I wish Aircel 3G was in my area to choose an unlimited 3G plan and get rolling. I could always top up the plan if I needed to continue with high speeds after exhausting it. Else, I could continue with 128 Kbps without toggling the network.