When my husband and I were younger, we heated our house with a wood burning insert and saved a lot of money in energy costs. But, we had the stamina and access to free wood. When we built our later house when we were in our 40's, DH opted to put in a gas fireplace. My son is in his 20's and he just put a wood burning insert into his fireplace. He has 4 acres of woods to get wood from.
I think it depends on your age and ability to do the work required for cutting and dragging wood through a forest and then chopping it up. If you have to pay for wood, I don't think it would be as much of a savings.
If you are going to sell in a few years, definitely a gas fireplace would be more appealing to most people.
Miss Prim