I've heard that Virgin Mobile phones share Sprint networks. Now it comes two identical phones- HTC EVO 3D for Sprint V.S. HTC EVO V 4G for Virgin Mobile, so on the hardware side, it can be the same. The problem is that is there any difference between the two carriers' network? Say, Sprint phones have a higher priority occupying the channel of the signal? If not, why would people pay an extra $30 to use Sprint instead of V.M.?