You might want to think about weighting and travel restriction. If you are flying to dive vacations, a lighter aluminium or kydex plate might work better. It will drop 4 to 6 pounds off your luggage. Plus, if you are diving say a 3mm shorty (or even full) on vacation you might find the SS plate too heavy.
That's a good thought for consideration. One thing somewhat unique to the Small-size SS plate (if that's what she ends up with) is that it's 3.8 lbs. instead of ~5-6 lbs., so it's a bit lighter. I'm fairly buoyant (she may not be), and with the Small plate I'm just neutral with a full 60-80-ish aluminum tank and no exposure protection. So I just add weight for air compensation.
However, I did just pick up a Kydex (light like aluminum) plate to try. I don't tend to fly, but there are a couple of reasons I wanted to try one (and it was used/economical):
1) For times such as certain steel tanks + warm water
2) Because I find that I'm often head heavy, and I thought I'd see how I would trim out with a bit more weight on my belt and less over my upper torso.
That said, if I were "home diving" in Seattle's waters, I think that for myself I would still get a steel plate first, and then figure that if it didn't work for traveling I would also get a lighter plate. I like that it's a bit heavier and also (depending on brand) that there is the option to add weight plates.
But that all depends on one's approach. At first I had the idea that I would try to be really "efficient," and get all gear that would be multi-purpose so that I wouldn't have to duplicate. But then I changed my mind and decided to optimize my gear for my near-future diving (which for me was warm-water), and then get additional gear if/when I started diving elsewhere. I'm glad I took that approach as I have really enjoyed the warm-water-specific gear.
Now if I could just get DIVING and try that new plate. It's just sitting here mocking me! :splat: