To my understanding (And that's limited here, I don't know a whole lot about him) Sanford is all but Ron Paul when it comes to the only votes. I remember hearing about them being the only two "No" votes often. He's an adulterer, and I don't like that, but when it comes to politicians, I'll take personal baggage over oppression any day.
I really don't think I can like Mike Lee anymore. Its not so much anything that he's changed as it is that I've changed. His comments on Snowden were absolutely horrific, and I think I've decided I really can't give him a pass on that. I don't view him as actively hostile/dangerous like I do Ted Cruz, but I'm still not thrilled.
Also, if it came down to a vote on Iran, and war fever was high in the GOP, I don't really think I could trust Lee to vote no. He's soft-spoken, but ultimately I think if Cruz dived in headfirst, Lee likely would too. Rand Paul I at least think would vote no on a real war vote, even if he isn't showing it with his non-binding resolutions.
Ultimately, HB's answer is the best possible one, though.