I have 2 years of ex-customer experience with Clearwire which I wish to share with you. Mostly because I am dissatisfied with Clearwire, but also to give potential customers a preview of what is to come.
I'll make it short because long texts are likely to be skipped.
You'll get a 5-10 second lag several times per hour. Not good if you're in a fight. Sometimes even the game connection drops, and you have to re-login.
This is probably lethal to ego-shooter players as well.
Make SURE you stop the domiciliation when you end the contract! And return the modem in time. Actually it does not matter whether you give notice or not - what counts is whether you have the modem or not.
If you tell them "hey why does CW not disable my account?" they won't understand, even though the technology would allow that. In my eyes this is a rip-off.
CW is actively blocking VoIP ports. At least that was the case some time ago. So inform yourselves thoroughly if you intend to use your VoIP phone. Why are they blocking it? They cannot guarantee a reliable connection.
Skype works. This is because Skype uses its own protocol and not VoIP. However, the lag will make you hear occasional blanks (~5 secs). It's not funny to keep asking the other person to repeat what he/she just said.
For those who are annoyed by English - why did you then read up to here?