Gel vs acrylic

Kara
What does everyone prefer? I have had my nails done for almost a year. I get an acrylic overlay with regular Polish and a gel (shellac) top coat. I've learned about gel overlays and I was wondering if anyone has experience with them? How are they? Do your real nails lift off from them like they do acrylic? How long do they last before you have to get them filled?