If you're planning on using the booster mode, doesn't the Frontier make a better booster than the Nautilus?
If space was an issue, I might go w/ a Radian.
If money was an issue, I'd go w/ a Maestro.
But, a Frontier, Nautilus, Maestro, Radian are the only *big* kid looking seats I can think of that I'd use. While there are other seats that harness to a decent height, Truefit, they aren't as *big kid* looking as the others. And, if her car seat values are limited, don't want child complaining about use, or he'll be done sooner than you may prefer, having spent the money on it...
If you already know her car seat values are no where near yours, do you want to spend $300 on a Frontier, that will be used for a year or two, fine if she has other children to pass it down to...but to use a Frontier in Booster mode vs buying a Maestro now, waiting for him to outgrow it & then buying the Graco turboobooster and/or SKJP/Britax booster, might upset you less...Not saying, suggesting or implying she would/will, just thinking about how frustrated I've been w/ ODS's pre-school friend's car seat (lack) of use. And, how over the top crazy upset I was when d/c lady put ODS into a booster instead of his Maestro...
tam