[maxvu]

Almost. Yes, you may still be charged. Yes, they may use the evidence of your refusal. As far as equivalence, no: the test itself is just one piece of evidence. Because refusal should ordinarily make it more difficult to prosecute DUI (for what is, comparable to the stop, a very small inconvenience), I think most states have an automatic license revocation penalty attached to it - usually around six months. Field sobriety tests (e.g. walk in a straight line), I think, are much less conclusive and do not have such requirement.

IANAL. Search for James Duane.