We have a Britax Parkway, Graco Turbobooster, Clek Olli, Combi Dakota, and Britax Frontier.
I'm not a huge fan of the Turbobooster, the only reason we still have it is because my girls have a huge attachment to the Cinderella cover on it! The Olli and Dakota are both low back, my older DD uses the Olli now and LOVES it, it latches in so it stays put and it's nicely padded, she just loves it. The Parkway is youngest DDs seat in DHs car (she rides in it once a month, maybe) and the Frontier is in my truck - with a harness right now. We love both.
We had a Sunshine Kids Monterey but DD isn't ready for full time booster use yet.