Convertible car seat help pls.

PinkJellyBean

We are just ready to move up to the convertible and just dont know how to decide which seats to buy.

We need 3 seats for our 3 cars (Nissan Altima, Jeep Grand Cherokee, and one that will be shared between our Mini Cooper Convertible & my moms car installed in either as needed).  We have a Britax Marathon that we received as a gift that we plan to put in the Altima.  Our DS spends equal time in the Altima & Jeep.

Which seat did you buy and why?  Trying to decide if we should buy another Britax for the Jeep or select another brand and then still need a lower cost (since not used as much) very easy to take in/out seat that will fit in the Mini.

All the name brand seats - Britax, Graco My Ride 65, Safety 1st, Evenflo Triumph all are well reviewed so what helped you make your decision? And any recommendation for the seat for the Mini?