Re: USB DataCard advice!
I have used tata phonton +, as others have mentioned, its speeds are pathetic, you get roughly around 256kbps, which is just about enough for browsing, but not good for the money you pay.
I have also used the Docomo wifi hub, the speeds are good but the device and the plans itself are pretty expensive...
I also have a Micromax MMX 310G universal hub, you can read its review here: Micromax MMX310G review
Also, here is the review for the Huawei E1550 USB modem, which I feel is better than the Micromax one... Huawei E1550 USB modem review
btw, hope you know about the BSNL 3G trick.....still works at some places...