Should I get the LG Rumor for kajeet or sprint?

Omg. That's the phone I'm getting for Christmas. I want one in blue or green. I have a pink Katana II and I have the Kajeet plan. The reason I am getting the rumor is because of Kajeet. I have it right now and it is so expensive even just to send a text. Kajeet costs too much so I am switching to Sprint. I think you should get Sprint : )