Huawei E3531 usb was my first dongle I bought 4 years ago and still it woorks fine I ave a 3g sim which I keep inside that dongle only and use it and it still gives good speed for browsing. I have used many dongles till now but this one was the best among those only because of the performance of this device I am impressed with it . can put one memory caed also in it hen we use it sometimes the green light blinks ad sometimes the blue light blink constant whene there is a constant light it means there is a good range of network and speed will be good. and ofcourse huawei is a company which helps the customers and react on their problems indtantly their support is good .
I am posting pics of my huawei E3531 below have a look at them .