So I'm looking to replace my (stupid) Tata Photon+ data card with a more reliable and faster 3G data card.Since I do a lot of road trips, which takes me to many non-metro and Tier 3/4/5 locations, I feel a service provider like MTNL would suit me best, since they have have BSNL's infrastructure to latch on to. Correct me if I'm wrong.Anyway, I think it would be cheaper to buy an unlocked device and plonk in any SIM that I want. So I have discovered these USB modems and I need advice on which is best and also where to buy (Ebay?)1. Huawei E17502. Huawei E1732 (or E173 - what is the difference anyway?)3. Huawei UMG1831Please suggest keeping in mind that I want a modem compatible with Win 7 Starter AS WELL AS Ubuntu.