I did a lot of research and comparing. I have a couple of friends that have iphones and I ended up buying the Captivate rather than the iphone 4 (they are both the same price with contract). My conclusions are:
Speed: Both great, will do what you need. Samsung tests slightly faster on most benchmarks.
Camera: both 5mp and good. iphone is better (best of any phone camera IMHO)
Video: Samsung had less blurring during movement, so it is slightly better, but they both take solid HD movies.
Web Browsing: Hands down, the Samsung and Droids in general win simply because of FLASH. If the iphone supported it, the decision would have been much tougher. I have friends that don't bother surfing the web because they are tired of missing content or seeing black squares on pages with their iphone. HUGE for me anyway.
Memory: Both come with 16GB of memory, but the expansion slot of the Captivate allows up to 48GB of memory. That is not a small point. Apple you have no future upgrade option other than a new phone.
Display: iphone's display is sharper with higher resolution (and smaller screen which makes it seem even sharper), but Samsung has vivid rich colors with a very black background. The Samsung also has blueish whites, but the super AMOLED screen is every bit as great to look at as the iphone. I say they both are great to look at in different ways, so you can't go wrong with either display.
Sound: - both sound good out of the headphone jack, neither really was noticeably better to my ears. The speaker on the Captivate is definitely better, however. That may or may not make a difference for most, but if you use speaker phone or listen to music through the little speaker, it's noticeably better to me.
Video conferencing: or whatever it's called. I don't like staring at someone's face through a phone, but if you do, the iphone is the way to go. Samsung doesn't do it.
Personalize: If you like tweaking or personalizing the look and feel, then the Samsung is better. Apple hasn't changed it's general look much and your customization is limited against any Droid.
Battery: Samsung tests slightly better, but they are both very good compared to what's out there.
Multitasking: Samsung wins
Build: The iphone feels more solid and looks sexier. The Samsung is lighter and has a carbon fiber styled back plate, but I like the build of the iphone better. Once you put a case on, they look the same. And you should put a case on it unless you never drop anything.
Most reviews I've read (that aren't tainted with misinformation and favoritism) put the Captivate and the iphone 4 on par with each other, both having strong and weak spots, which leaves it to personal taste.
I have time to pay $25 for a restocking fee and exchange for the iphone, but I can't justify the Apple given what the Captivate offers, even though I always thought that I'd own an iphone and am still open to hearing a compelling argument.
I would like some more discussion in hopes that I'm not missing something, but I think I'm sticking with Samsung and the openness of the Droid. Please add facts or arguments rather than the "iphone is cool, you should get it" or "Droids are better" stuff please.
Both phones are top tier.
