The
Regent is absolutely not for a newborn. Bare minimum: starting at 12 months old, but ideally kids should stay rear-facing until the
maximum RF limits of the
convertible seat ... this means you would lose at least 1 year of use of the seat since it expires 6 years from Date of Manufacture (most carseats do). My website explains in more detail why it is soooooo important to keep kids RF as long as possible.
Britax more comprehensively crash tests their products & issues recalls
before an actual injury while Dorel Juvenile (parent company of Cosco, Safety 1st & Eddie Bauer) generally waits until they're forced to recall.
Britax does have more ease of use features & lacks the serious misuse risk of the top harness position in the Cosco Alpha Omega (described in other threads). Cosco does a great job advertising the Omega, but very very few parents are pleased with the seat long term & almost always end up buying replacement seats eventually anyway because the child has outgrown the harness yet is no where near ready for a
booster, etc.
If $ is tight & you will absolutely use the Omega correctly (read that manual thoroughly, ask questions here, call the manufacturer, visit your local technician) then it should be a fine spare seat. But, ideally, yes, I would prefer to exchange it for a
Marathon or especially a
Recaro Como (at least as respected as Britax, but fits longer both RF +
FF).
I don't foresee any serious installation issues with your vehicles, but when as little as 5% of kids' seats are used correctly, it would be wise to have your seat checked
