After long deliberation, I have purchased high-backed booster seats for the boys. If you don't have small children, you are not very likely to know much about the current various options for child restraint systems. And if you do have small kids, you know how many choices are out there.
One member of my mothers of twins group sent an email with a YouTube link about why you should keep kids in a 5 point harness seat for as long as possible. It was, of course, a tear jerker. You know, a story about how they put their son into a booster, then got in an accident and he died because the seat belt failed. And how if he'd stayed in a 5 point harness seat, he'd still be alive. (I'm not trying to minimize the loss, but to summarize the video. I can't imagine losing one of my kids in a car crash, or in any other way.)
So I started thinking we needed new, bigger seats with harnesses since the boys are outgrowing their current seats. Research on various sites muddied the waters, in my opinion. I couldn't find anything other than the video that talked about prolonged use of the harness. I felt like this horrible parent for even considering a shift to booster seats. It was suggested by someone near and dear that perhaps I was overreacting. I continued to stew over this for a good long while. Several months, actually.
In the end, I decided that since I survived a child restraint free upbringing, and since my kids are perhaps the only children alive who haven't unbuckled their straps in protest, I would go with the boosters. Every time I went to Target or any other store that sells car seats, I'd examine them carefully, then leave to think on it some more. Maybe I am a bad mommy for reaching this conclusion, but I have to draw the line somewhere, right? I always make sure my kids are buckled up, I'm a careful driver, and last but not least, Kemper and Rowan are SO happy with the new seats I'm convinced I made the right choice. Rowan thanks me for buying him a new seat every time we get in the car. It's only been a few days, but they're still very excited about using real seat belts like mommy and daddy.