car seat recs for a prius v - frontier vs radian?

Looking for some insight as we look to purchase two new carseats!

We have two boys: a 3.5yo who weighs 37lbs (don't know his height off the top of my head - but at last check up he was beyond the 100th percentile for height) and a 15month old (measurements at his last check up were 23lbs and 32").

Our older son is forward facing and the younger one is obviously still rear facing.

Our current car seats: a Graco Nautilus and a Britax Boulevard. They are in our 2012 Prius V.

We are looking to purchase two new car seats so that we don't have to shuffle seats between cars. So two seats will remain in the Prius V and two seats will be in a 2013 Prius. The ones in the Prius V will be the seats primarily used, and those in the regular Prius will be used less often.

Right now we are considering the Britax Frontier 85 for our older son and the Diono Radian RXT for our younger son. Although we could just as easily do two Radians. Or something else?

Any idea what would fit in the Prius V? or the regular Prius? (I read another thread on here that a mother had trouble fitting any non-britax car seat rear-facing in her Prius V - but it didn't look like she'd tried the radian...?)

We like the idea of having seats that will last so that we hopefully won't need to purchase anything again down the road. The Nautilus is fine - although the construction sometimes feels cheaper to me than our britax. I like that the Frontier and Radian both have greater height and weight limits than the Nautilus which is why i'm not leaning towards getting another Nautilus. I love our boulevard rearfacing - but when we used it forward facing previously with our eldest - I had trouble tightening it.

Any and all suggestions and info welcome!

I don't know about the Prius V, but we have a Frontier 85 and a RF Diono Radian RXT in our regular Prius. The RF Radian is fine with the angle adjuster, but probably wouldn't be without it. They are both outboard, because I couldn't get them to fit next to each other.

Our Prius is from 2006 but we currently have both a Frontier 85 (only the long belt path felt secure) and an RXT Radian installed (seatbelt install; I have had the Radian both RF and FF, with the angle adjuster). They are both outboard. (The only seat that fits between them is a Bubble Bump - I don't think we have ever gotten a child, never mind an adult, to sit comfortably between the two seats without a booster. But that may not be important to you - it's only a very occasional consideration for us.)

I like them both fine, they have served us well so far. The Radian seems more versatile to me - easier to install, and narrower. So you might do two Radians, and have more room between the seats, or install them side by side. We've also taken the Radian on trips where we've flown - it's heavy but I love that it folds up.

If you go with the Frontier - then I 'd put it/them in the car where you don't need to install/un-install frequently. I think I've moved DD's Frontier only twice in 2.5 years.

DS is about to outgrow his seat in DH's car so I am thinking about either the Frontier or Pinnacle 90, but he might need a replacement before either of those are released. So I might be reevaluating the seats on your lists, sooner rather than later! Best of luck with your choice!

Thank you both! Any sense that one seat is better quality than the other? One more comfortable then the other? They look pretty comparable re. Height/weight limits - is that true? Or do you feel like your kids "fit" better in one over the other? does one fit in the car better than the other?
Good to know we'll likely need the adjuster if we go with the radian - luckily it's cheap!

Both seats are very sturdy, and very heavy! Height/weight - DD is in the Frontier, she is about 55 lbs. and 53". Plenty of room on either side. I do need to bump up the headrest again as she had a growth spurt, but she's still got another year or two, I'd say. (If I recall correctly from last year's well-child visit, she's 50-75th percentile at almost nine.)

DS is about the same size as your 3yo (he's a very compact five, though), at 34lbs and 41". Has at least a good 6-8 inches of head room in the Radian. (He's just outgrowing our Boulevard 70, torso-wise, for comparison.) Just eyeballing it, I'd say it's cut narrow, so if either of your kids are built like linebackers you might want to have them test the seat for comfort, width-wise. But DS is plenty comfy.

ETA: Was re-reading some of the other threads here about Radians and Priii (heh ) which reminded me that the sides and base of the Radian are lower vs. Britax convertibles (the Frontier is FF-only, of course), so it's easier to load an RF child into the seat. DS climbed into his no problem, whereas I always had to help him into the Blvd. So there's that benefit, at least for one of the seats.

Random comfort note: Both the colorways we chose were made with a slicker, nylon-ish fabric. (We have the red RXT, and a Pink Sky Frontier, though I doubt you'd choose the latter. ) On the plus side, it wipes clean very nicely, so, less fiddling to get the covers off for washing. On the down side, I just like the feel of plush covers better. (I also dislike the mesh part of the Frontier's seat - catches crumbs and stuff.) Just something to check, if that matters to you.

Again, the Radian is narrower, so it just fits in more places than the Frontier, and I find it easier to install, as long as you have the adjuster. I've installed it in my car, DH's car, and the rental we had last summer. Very straightforward. But both of the seats fit in the Prius just fine. You could even do two of each, if you preferred.

(Most value-priced option would probably be two F85's. My instinct would be to get two Radians, or to split the difference and have one Frontier, and one Radian available for air travel. Or, since you have a younger one who can use his brother's seat later, I'd consider the upcoming Frontier/Pinnacle 90's, plus a Radian. Just my two cents and YMMV... like I said, I'm considering some of these things for our car as well, so it's been on my mind! )