Major Purchases: Safety 1st

Which Booster Seat: Britax Frontier 85, Safety 1St Vantage, or Go Hybrid?

I value your opinions! Both my kids (4 and 6) have outgrown their Britax Marathon and need to move to a booster seat. I strongly prefer one that offers a 5 point harness to secure my kids for as long as possible. I found the following three: Britax Frontier 85 http://www.toysrus.com/product/index.jsp?productId=4082061 Safety 1st Vantage http://www.toysrus.com/product/index.jsp?productId=3513390 Safety 1st Go Hybrid http://www.toysrus.com/product/index.jsp?productId=4008520 Do any of you ladies have any of these booster...