<human>: I guess I'm in the market (or deciding if I'm in the market) for a new booster seat for my little Peanut. 

She'll be 6 in less than 3 months, and she's at about 43lbs (she goes between 42-43). She's currently in a 5-point harness car seat, but the weight limit for the harness belt is 40lbs. We live in Washington and I could have switched her to a booster at 4 years old, but wanted to keep her in the 5-point as long as possible. 

The car seat she has is a convertible (rear/front/booster), but I don't know if I should keep using it or go with just a booster seat. 

The majority of parents in my circle of friends use Britax seats but that's mostly because the two "hip" moms bought Britax and now that's THEE seat to buy! 

So I'm wondering if I should buy a Britax because it's a superior booster seat, or if there's a better (safer) seat out there, or if I should just remove the harness straps from Peanut's current seat and start using the car's seat belt. 

Do any of you use the Britax booster seat and if so, how do you like it? Any thoughts or reviews on other booster seat models? Should I use a high backed seat or a backless seat? Should I find a car seat that has a higher weight limit on 5-point harness?

Can you provide a brief overview of the text?
<bot>: Please give your advice/reviews on booster seats, because I trust your opinions more than my circle of friends who tend to be all about the latest fad and brand names.