Here's my post-initial experience comparison. Since this is the Aria sub, I'll swap this so the Pro's are a win for Aria, and the Cons are a win for the Captivate.
Pros:
Aria is better for the average user who just wants stuff to work and doesn't want to dick around with "fixing" things right out of the box.
Aria feels like a better build. And I'm pretty sure after a years worth of use the Aria will (unless dropped/mistreated) look the same as it does right now. The Captivate is already showing reflective wear on the back cover. The edge metal should stay pristine forever, but that cover is going to show a lot of wear.
Aria call quality seems infinitely better. This isn't a side by side comparison, but I recall being impressed with the Aria, and just satisfied that the Captivate (which is more of a mini-tablet than a phone) can make a call and be clear enough to carry on a conversation. To the Captivate's credit, I haven't spent much time on it making calls yet.
Aria has no "death grip" issues worth noting, however the Captivate has a serious issue on the back lower right side that can be, in unnatural testing conditions, a complete killer.
Current support for the accelerometers seems to be better for the Aria. Captivate appears to need an adjustment who's setting option is currently elusive.
Battery life may be better on the Aria. I've got my screen pumping out full brightness though so that's not helping any.
CONS
With all this talk of a "retina display" and the scientific breakdown of what the eye can make out pixel-wise, you will not believe how breathtaking the "inferior" Captivate screen is. Not only is it crisp and high def (without technically meeting the specfications to be called such), but the colors and the contrast are unbelievable. We're talking eye-gasm here, each and every time.
Live wallpaper is somewhat of a gimmick you can shrug off, but I love em.
Video capture isn't even a comparison. This records in quality that when you are told it's 720p, you believe it. And pictures look great. Also, back to the screen, VERY visible outside. Still some wash in pure sun, but even just putting your own shadow between the sun and the screen and you could easily watch a video outside or use it as an ereader and be perfectly happy.
Gaming on the Captivate is phenomenal, and will only get better.
16gb native storage.
Future-proof: The Captivate inarguably has a longer life ahead of it than the Aria does, at least as far as support goes. And as most of us know, each new version of Android extends the life of a phone's potential to be compatible with future needs.
