If that's what they're really doing now, then you just have to do a cost analysis to compare apples to oranges. Yes, with a lower interest rate (even if it's not the BEST interest rate out there) your payments will be lower, but are you going to refi for 30, 20 or 15 years? There are so many variables that I can't say whether it's a good deal for you. DH and I refinanced once and not only lowered our interest rate, but went from 30 to 15. The payment was not much higher and the house was being paid off much more quickly. (It was a big rate drop.)
If it's much of a rate drop at all, and there are truly no costs to be rolled back in (as has happened to friends of mine) then it's worth running the numbers on. Heck, even if costs are rolled back in, it never hurts to do the math and see if it's worth it.
But here is something to consider. Run a separate set of figures.....Where you PAY closing costs and get the lower interest rate. See how long it takes to recoup those refi expenses. Two years? More? Less? After you "get that money back" that lower interest rate will save you $X every month over the "no cost" amount. If you plan on staying in the house several years, it may make more sense to pay the refi costs and get the lower rate. It all depends on how the numbers fall.
So much depends on the rate you currently have, what the no cost rate will be, the "cost" rate will be, how long you plan to stay in the home, etc. There is no one set answer because there are too many variables and only you have the numbers needed to get to the answer.