Rubio made an early splash as an attractive hispanic tea party Republican, someone who ran and won against a truly pathetic Charlie Crist (a man so staunchly Republican that he ran as an independent when he lost the primary, and has since joined the Democrats). Early in his Senate career, however, he signed on to a potential amnesty deal with McCain, Graham, and the other usual suspects. The deal failed, but his participation in it marked Rubio's shift away from the tea party values and towards a more establishment-friendly position.
He has since given interviews in which he moderated his position -- but his interviews, given in Spanish, tell a different story. In those interviews, he supports the Obama amnesty and continues to support immigration reform along the lines of the Gang of 8 Senate legislation that got so many conservatives feeling betrayed.
I do not support Rubio for president because Rubio cannot be trusted on immigration issues, and as he spends time in the Senate, he continues to damage his record by aligning with the establishment and even sometimes with the Democrats. Time after time, on issue after issue, he has reversed himself from a grass-roots position to the Establishment position. What this tells me is that he cannot be trusted. He will say what he has to say to get elected, and then do something else. The record of dishonesty continues today, using the cheap trick of Spanish language television to tell one audience one thing and everyone else something different.
As they say, he coulda been a contenda... but he ain't anymore.
He thinks the surveillance state must continue:
Anyone who is for continuing, expanding, and making permanent the current surveillance state will never have my vote.
He wants to raise taxes:
Government is not a wealth redistribution mechanism.
On the plus side, he opposes federal subsidies for ethanol, and has been moderating his position on immigration somewhat. He is sponsoring legislation to relax the gun laws in DC, but frankly, I think this is a strategic mistake; DC's laws are so draconian and the local government so incompetent that they make great fodder for good legal precedents. On the other hand, Obama will never sign it, and forcing him to veto it may have value if anyone still believes he doesn't want to take their guns. On the gripping hand, Obama won't be running for anything; why give the Democrat Senators the chance to vote for something pro-gun that's just going to get vetoed?