Help choosing Britax for four month old

Hi All
I have four children, my newest addition is four months old, only about 13lbs and is in Chicco key fit infant seat right now. He HATES the car seat and screams bloody murder every time I put him in. Not sure if it will help but I want to get convertible seat , hoping it may be more comfy.
I have only had the roundabout in the past. I know a lot of people suggest the Marathon but I have two concerns, #1 it does not look very comfy to me # 2 Baby's seat is behind drivers side, I have Nissan Quest minivan.It is fine for me because I'm only 5'3 but on weekends hubby drives and he is 6'3 and pushes the seat back pretty far.
My other kids are 11,8 and 5 1/2 so I feel sort of out of the loop with the latest carseats so any help would be greatly appreciated!!

Is there a particular reason you are only considering Britax or are you open to other brands?

Your son may or may not fit into a Britax convertible at his length, the bottom slots are approx 9/10" which is pretty tall for lowest slots.

There are other convertibles which are great for smaller babies and IMHO last longer than the Britax convertibles due to taller harness slots and taller shells.

Sure, I'm open to other brands. Just want something very safe and as comfy as possible

oh~ he is 26 1/2 " tall

Yes, at only 13lbs I would definitely try before you buy to make sure the bottom slots are low enough for him. Another option is an Evenflo Triumph Advanced (EFTA). It seems like the slots start a little lower in it and it doesn't take up any more space RF'ing front to back than most infant carriers. There are plenty of wonderful options out now that aren't necessarily Britax (and believe me, I love my Britax! LOL) that might be a better fit for your little one. Do you have a BRU or Buy Buy Baby or anything like that nearby? I would suggest checking the seats out in person and checking their fit in your car before making a decision. If you would like to RF as long as possible, there are 3 seats out now that RF to 40lbs. They are the MyRide65, the Radian (all models of it), and the Complete Air. I know BRU carries all of them in most of their stores except I personally have never seen a Radian IRL. HTH!!

My baby also screams. She HATES the car seat. She is in a Keyfit as well. We also have a Blvd. I put her in it and it helped for a few trips then she was back to screaming in that all the time. She will be 3m next week.
So just be warned switching to a convertible may not help. If his shoulders are at or above the 2nd slots on the Keyfit he should fit fine in a Britax Blvd.

The 2nd choice after Britax would be a Radian or True Fit.

I have some pics somewhere floating around of River in her seats.

Yeah, I'm pretty sure he will still scream but the keyfit looks really uncomfortable to me so its worth a try to change. Is the BLVD the best choice for Britax? I have a BRU here but have never seen the brand Radian? Is Safety 1st the one with side air ? I saw those at BRU.
Is that a good seat?
When my other kids were young Britax was the one that was supposed to be the best so I would love to hear about what brands compare or exceed . Thanks!!

Britax used to be the be all and end all. Easy LATCH connectors, built in lockoffs, higher weight limits and shell. But now they have been surpassed by taller shells, better weight limits, longer lifespans, and lower prices. Plus they don't fit newborns well. Of them we generally don't recommend the regular Roundabout or Diplomat because they're outgrown so early. The Decathlon still only has a 33 pound rear facing weight limit, so we don't recommend it. The Advocate is a huge waste of money, as is the CS feature. So generally we recommend the Roundabout 50, Marathon, or Boulevard. No one is best over the other. It's what you like between them. The Roundabout 50 goes to 50 pounds forward and 35 pounds rear with top slots about 17". The Marathon and Boulevard go to 65 pounds forward and 35 pounds rear with top slots just shy of 17".

The Learning Curve True Fit has a 35 pound rear facing limit, 65 pounds forward, 17.5" top slots, lots of leg room, lots of shoulder room, pretty easy to install. The TF Premiere has an anti-rebound bar that works similarly to the tether in a rear facing Britax. The regular is $150-$190, the TFP is about $270. It also has a seven year lifespan.

The Sunshine Kids Radian isn't at BRU. Try a specialty or boutique baby store. They have a 40 pound rear facing limit, 17.5" top slots, tall shell, eight year lifespan. I wouldn't bother with an 80 unless you adore a cover, nor the XT unless you adore the wings. They all will be outgrown by the same torso height, so most kids won't make 65 pounds, nevermind 80. $200 for the 65 version. $280 for the XT. This seat can be a bear to install, and it's usually pretty reclined. It folds for easy travel, but it doesn't fit rear facing on planes.

The Safety 1st Complete Air has the air cushions. Piper said it was very comfortable when she sat in it. I have no experience installing this seat. It rear faces to 40 pounds, forward faces to 50, with 17.5" top slots. It'll get kids to 40 pounds. Piper would have outgrown it rear facing about six months ago at 6.5 years old. $250. I was more impressed with this seat than I expected to be, but I still think it's overpriced.

I'd also look at the Graco My Ride, with the 40 pound rear facing limit and 65 pound forward, with about 16" top slots, as well as the Evenflo Triumph Advance (35 pounds rear, 50 pounds forward, 17.5" top slots).

Honestly, Britax seats now are at numbers six and seven (and eight for the RA50) for my top carseats. The higher weighted, higher shelled, higher top slotted, more leg room, lower priced, and in some cases longer lifespanned seats have passed them over.

Wendy

As usual, I totally agree with Wendy. I have a True Fit and if it were available when my son got his, would have gotten the True Fit Premier (on sale for around $220 on www.learningcurve.com if you register and use code LCFRIEND). It has TONS of RF leg room, tall shell and top slots, but it doesn't sit up on a base like the Britax seats so, do it takes up about the same or less space front-to-back than they do. I would buy it again in a heartbeat.

I saw the new Graco MyRide today at Target and have to say that I was pleasantly surprised! I didn't really expect to like it, but I did. I just wish the shell was a little taller. They also had a new cover for the Evenflo Triumph Advance that was REALLY nice. I was impressed.

Ok ~ thanks so much everyone, yu have given me so many other options! I'm all for cheaper and last longer My kids tend to be tall but really light. My five year old is only 42 lbs and my 8 yr old is about 53 lbs so I think having a seat that is taller is what I need most.