For Aircel- You will get the 15k to 20k speed for browsing. and for downloading you will get the 3k or 4k speed.
If you want to use internet for basic needs like Email checking and working on live projects (SVN) than AIRCEL is worth it..
But you want some more speed or download speed than go with Airtel or Idea. In GPRS Reliance is the Best for Speed but did not having any unlimited plan.
New GPRS service in Pune
Idea’s Tariff -30 Rs Per day(Unlimited Use)
Airtel Tariff – 25 Rs Per day (Unlimited Use)
Aircel Tariff – 3 Rs Per day(unlimited Use) (98 Rs for Month pack)
If you take any sim from any service providers who are offering unlimited GPRS service. They may not charge you for downloading for any thing.
Some GPRS providers offers surfing is totally free. This is absolutely true but you need to know about surfing. only surfing means only HTML content displaying. If you check on HTML site then you will be fitting in to that scheme.(Google-only HTML base except image logo) As per my knowledge most of 99% sites are media files and media content.(For exmaple- yahoo.com, youtube.com or any site which having images or flash or video.)
So in Unlimited service nothing is chargeable. but in download case all sites are down loadable.