Help Me Decide Between These Convertible Car Seats

I don't think that you will be putting your son in this right away which is probably why you are asking but when you are ready to put him in a seat (when ever your choice may be) I would pick the graco one (out of your picks.) But I do highly recommend the Britax. They are pricey... but its looks like you have some time... so just watch for sales. I got my sons marathon for $180 and I found my daughters for $40 (brand new still in package) at goodwill. So you just have to look around and be patient. If your not so sure about a carseat by a cheaper one at walmart and see what you like/dislike about it. It could always go in your hubbies car (that what we did).

Good luck!

If I had to choose one of these for a 6 month old, I would only choose the Radian 80 as it is the only one that can rear face and you want your child to rearface to AT MINIMUM 12 months AND 20 lbs. The AAP has actually recently come out with guidelines to keep your child rear facing to at least 2 if you can.

If you are looking for a seat that will last you a long time for a 6 month old, I would look at:

-Graco MyRide which can rear face up to 40 lbs, ff to 65 in a 5 pt harness
http://www.albeebaby.com/graco-my-ride-65-convertible-car...

-First Years True Fit which rearfaces to 30 some lbs and then ff in a 5pt harness to 65 lbs
http://www.albeebaby.com/the-first-years-true-fit-convert...

-Britax Marathon which can rear face to 33 lbs, and ff to 65 lbs in a 5 pt harness
http://www.albeebaby.com/britax-marathon-convertible-car-...

-Evenflo Symphony which can rf to 35 lbs, ff, and then convert to a booster, also VERY easy to install as it practically adjusts itself
http://www.albeebaby.com/evenflo-symphony-featuring-surel...

All these seats are equally good, I would just take your son to the store, see which he fits in best, which is easiest for you to install and which is easiest to use and you will use properly every time.

I have two of the above seats for my 15 month old and have installed the Symphony as well. I am also a reg child passenger safety tech so if you have any questions re installation or anything else, let me know. Just make sure you read the manual thoroughly and follow the instructions and get a tight install (no more than 1 inch of movement at the belt path). And of course, make sure your child is secured properly in the seat.

i don't think the nautalus goes rear facing but i love the seat

I love my nautilus, but it does not rear face. It switches from a 5 point harness car seat to a high back booster to a no back booster.

We use the Evenflo Triumph as our convertible car seat and love it!

The Nautilus is NOT a convertible carseat. It does not rearface. The AAP recommends that children rearface as long as possible, up to the weight/height limits of the carseat. I would not recommend any of those on your list. Instead, check out the new Graco My Seat (rearfaces to 40lbs.) or a Britax Marathon (rearfaces to 35lbs.). Both of these harness to 65lbs, forward facing.