My two cents. Had a moment, liked it, but ... eventually went to the hero.
I had the moment for two weeks. The screen was great, but the build was cheap. I tried to get used to keyboard, but the placing of the keys were just terrible for me. True, I could be sort of fast with it, but I would constantly have to keep looking at the keyboard and not at the screen which was annoying. Also, the directional arrows on the keyboard just seemed extremely weired to me. And the spacebar was terribly placed. Why couldn't they have made the keyboard more like the touch pro from HTC (a well, built slider, in my opinion). The onscreen was actually decent on the moment, and I got pretty fast. I would say I was almost faster using the moment's onscreen keyboard than the phsyical, which makes the whole reason for getting the phone (phsyical keyboard) be pointless.
Apps ran fast, but the funny thing is, the HTC hero seems a lot snappier than the moment, perhaps due to the software optimizations on HTC's part. I thought I wouldn't care about the whole sense UI, but it rocks, and I actually like it. Still adjusting to typing on the hero. Never be as fast as my treo, but I can deal with it. We all know the moment is technically faster, but if you know anything about cpus, processor speed alone isn't everything if the underlying code isn't optimized, or just crap. If the Hero does lag, I haven't really noticed. I'm biased, of course. I come from a long line of WM devices where lag was the norm; the hero flies, as does the moment. Anything is better than WM lag.
Since exchange is where I keep my stuff (via work), that was key. Both units sync them well, but the Hero, for some reason, does not sync tasks, yet. Hopefully this is fixed in the future. That being said, the hero's exchange email program is miles ahead of that mozier crap, and I really like that. Hopefully 2.1 fixes that. Nevertheless, mozier does the job, and does tasks.
Battery life -- I could have overlooked some of the flaws of the moment. Really, it seems like a decent phone. However, the battery life is the worst I have experienced in all my experiences of owning pdas/smartphones. I realize there is a battery meter issue, with it not being measured right. I tried to optimize it, and do all the tricks laid out in these forums, but the battery life still sucked. No problem; get an extended life battery, which is what I usually do. I buy my batteries, usually from seidio, and I contacted them. According to them, they have no plans to make batteries or any accessories for the phone. This may change,but if seidio isn't doing the batteries, I'm sure a lot of other companies aren't going to throw there weight behind this phone. I don't have time to wait. I could get an OEM battery, but the reason why I like the extended batteries is, I use the heck out of my phone, and I hate, hate, hate doing battery pulls. Seidio batteries have been very good to me, and I often don't have to charge them for days, which is great because I am on the go a lot. I could have ignored everything else, but since the prospects of getting an extended battery from any company were looking bleak, this was the dealbreaker.
On top of that, it seems like Samsung isn't pushing this phone, given their lack of advertisment money for sprint. Did they just push this thing out, and forget about it?
Which leads me to reputation; I've owned many HTC phones, and I've had good experiences with them. This is my first samsung phone, and from my perspective, they are not known for quality phones. The moment does seem like a solid phone, but it just seems like HTC is backing up what they make a little bit more. The build quality on the moment also seems more solid as well, but I think I am going to avoid sliders from now on, unless they are really sturdy. I kept getting the feeling that the slider was going to snap off when typing.
Just my observations