All of the carriers have their way of detecting tethering. Including Sprint. Sprint some time last year decided to enforce the 5GB cap on their $30 hotspot plan. The cap had always been there but until late last year they had no ability to detect who went over. Now they do.
That said, I also chose TetherMe after doing my research. I could not find too many people complaining about being caught with it so I went ahead and got it.
In my case I may have some small protection in that I already pay Sprint an extra $20 for a 2GB hotspot on my iPhone. So, if Sprint DOES see me tethering
well, I already have a legal tethering plan - up to 2GB anyway.
To use TetherMe make sure WiFi is off first. If you are in an area that has a WiFi network you've connected to you will either want to move out of the area or find some other way to disconnect from that network. before you turn WiFi off.
Go to Settings>TetherMe and press the Peronal Hotspot button. That should take you to the hotspot area where you can turn on the hotspot (note that this is grayed out if WiFi is on). Choose your method, WiFi, USB, etc. If you choose WiFi the iPhone will create a new wireless network.
Connect your laptop to the new wireless network using the password you set up. Once that's done, you're online.
The hotspot (not TetherMe itself) uses your cellular connection. That's 3G, EDGE, LTE or whatever it is that your iPhone is using in your area. That means that if the connection on the phone itself is bad or slow, data transfer to your laptop will also be poor.