From Rasmussen:

The latest Rasmussen Reports telephone survey of Likely Voters in Florida shows Rubio with 38% of the vote and Crist at 33% if Congressman Kendrick Meek is the nominee. Meek earns 21%. Only one percent (1%) prefer some other candidate, and seven percent (7%) are undecided.
If billionaire Jeff Greene is the Democratic candidate, Crist gets 37% support to Rubio’s 36%, with Greene trailing at 20%. Two percent (2%) like another candidate, and five percent (5%) are undecided. […]
In both matchups, Rubio gets 66% of the Republican vote, and Crist draws 25% support from his old party. If Meek is in the race, he earns 48% support in his own party, while Crist picks up 36% of the Democratic vote. If Greene is the nominee, Democrats break even between Greene and Crist.