A. It really does depend on your application - there is no one size fits all! While many residential & SOHO users using these for cable/dsl/dial-up replacements will often target the lowest-cost routers, there are other important criteria to consider when selecting what cellular router to use. Some criteria include:
Compatibility with your cellular data card. Not all routers support all data cards. Some routers only support 1xEVDO data cards from traditional CDMA carriers such as Verizon, Sprint, Alltel while others only support a specific form factor such as PCMCIA or USB data modems. Still other aircards from one carrier may not be supported by router firmware while others are more
Portability and form factor. Some users get the cellular data card for travelling and as such prefer portable routers. These cellular routers come in different shapes and sizes from bulky non-traditional shapes to slightly larger than the width of a PCMCIA data card.
Networking features supported such as support for VPN passthrough among others. Remember that the cellular routers convert from cellular Internet to regular WiFi 802.11g. Once converted users expect to get the same features & performance found in traditional WiFi routers. This is not always the case.
Stability and reliability. Again not all routers are created equal. These routers gained mass adoption less than 3 years ago so manufacturers are still trying to fine tune them. Some manafacturers are clearly ahead of the game on this front.
Ability to attach high gain WiFi antenna for increased WiFi range more
Availability of ethernet uplink ports for failover or redundancy in addition to any other fancy features such as dual modem support, Bluetooth CTP profile support, Print server support, ability to tether phones, integrated print & storage server, integrated lion battery, etc
