Straight Talk and Net 10 are now offering LTE to their customers. Both these prepaid services allow you to bring in your unlocked GSM mobile phone and use it. All you need to do is pay for the sim and a monthly fees.
Members over at our forums have been reporting good download speeds (as can be seen in the screenshot above).
Of course both Straight Talk and Net 10 are knows for throttling your data in case you are on unlimited plans so please read the terms and conditions carefully before jumping onto any of these.