Another Car Seat Question?

I have spent 4 days on the computer researching convertible car seats. I am having a horrible time making a decision. I think I have narrowed it down between the Evenflo Triumph Advance and The First Years True Fit. My son is 10 months old, 23lbs. I would love to get the Britax Marathon, but it's not in our budget. I've read so many reviews that they are just confusing me even more now. My main concern is safety. We live in Florida and i've never been around so many bad drivers. Can you help?