I did this with my student loans. I got a balance transfer offer for 2.99% for the life of the transfer, got approved for a $30k limit, and transferred over everything I could. The fee was 3%, but it had a $100 cap, so that was all I paid. My student loan rate was 6.8% as well, so even losing the tax deduction I still came out ahead, plus credit cards don't follow you for life like student loans. The risk I took was that, if I had run into financial hardship, I no longer had the ability to defer the payments.
It worked well for me, and I have since paid it off. I was fed up with dealing with Sallie Mae's customer service, and was thrilled to be able to drop them.