Feedback on using Starhub prepaid data roam in US
Arrived at SFO today and before travel specially purchased Starhub prepaid SIM for $18 and enabled 1.2GB of data on it for $12 (it came with $18 credits). Here are observations:
The conclusion: if you have to have data network available in all places you go, then please a) get a phone/device which works at 4G frequencies in US and b) use/purchase SIM card which uses AT&T network. It will cost you 4x-5x the amount of mentioned above but you won't have accessibility problem.
Now a little bit more detailed explanation, it works, but... that but would make some people not to use this option.
First, I specifically took with me a small mobile 3G/4G/cell wifi router (called mifi device as well) which worked fine in Singapore, Indonesia and Malaysia for this purpose - the same SIM card shows 4G connectivity after powering on and speed was good. However in US the device could not connect to T-mobile (destination roaming network) for speed >2G. Which makes it completely unusable here. If you leave settings in 'cell connectivity' as auto, it will take about 3-5 min to connect to the Tmobile network. You can speed things up by logging on to router's management interface and selecting Manual and after that - Tmobile network, but it won't affect the speed it will connect - you will have 2G at the end.
Then I put the SIM card into my Singapore iphone 6 and after restart it came with 3G. It will NOT be working with 4G here because the phone does not support required frequencies.
Now the bad part of the situation is that coverage disappears in number of places. Moreover, while it shows that there is no coverage at the particular area, T-mobile's own SIM at the same phone shows excelled 3G connectivity. Even if you have 3G, it also introduces huge delay - tested number of times and it showed as 550ms and very low up/dl speeds - like 450kbit down and 200kbit up.
If you do not mind paying US30/SGD45 for a SIM card for the time you are in US - go for it. If speed/connectivity coverage is not that important for you then this option might work.
I personally won't use it again during my visits in US.