I purchased the Muama Ryoko "4G Internet Router" and a 5GB service plan from Viaota. They don't tell you will have to pay monthly for a service plan when you buy the device. You find that out after it arrives and only has 500MB of data on the included SIM card. The Viaota plans range from $15 to $39 per month. I bought the device because there are places I visit that have no service for my mobile phone provider. Ryoko claims they work with AT&T and that provider does have service where I need to work.
Although slow, the Ryoko device sometimes works. But minutes later I get messages saying the Internet connection is lost. I spent hours on chat with Ryoko and Viaota "support" and they were of no help. They would either parrot the instructions on the website or in the manual. I got the feeling after wasting all that time that no one on the so-called 'support' group actually knows or has even seen the Ryoko device.
I will try to return the Ryoko device for a refund but I'm not optimistic based on the 'service' I have received so far or have read in the genuine reviews. Most of the "reviews" I've read online seemed to have been written by Ryoko employees and they all repeat the glowing hyperbole on the Ryoko website. Had I done due dilligence, I have have noticed that red flag.
Hopefully you are reading this before wasting money on a Ryoko device and undisclosed Viaota service plan. The bottom line is that Ryoko only reliably worked for me in places I didn't need it at all. My mobile phone provider's data plan (including hot spot and tethering) are less expensive, faster, and more reliable. If Ryoko doesn't work everywhere there is mobile phone data service, it is a waste of time and money. Don't buy one!