I was using the Huawei MiFi E585 which I bought 4 years ago till the battery life decided to give up on me. The battery will go flat after about an hour of usage. On top of that I am spoilt with 4G because the 3G speed is way too slow in Singapore, due to bandwidth congestion.
I wanted to get a 4G mobile wi-fi modem last year but it was still pretty expensive, but this year it seems the prices has drop quite a bit. I bought the Huawei E5372 4G Mobile Wi-Fi Modem from a reseller (romz1983) in HardwareZone Forums for S$230. If you are interested in getting it, check out the forum thread, WTS: Great MIFI sale from $90 Huawei E589 E5776 E5331 E5220 E5151 ZTE MF60 Wifi Router. He offers other models as well.