I had an Evo for about 26 days before returning it.
I have a Vibrant now for 5 days.
Evo on Sprint:
Pros:
Larger Screen
Kickstand for watching TV/Movies - it's such a little thing, but nice to have.
TV Service included in price
Availability of accessories (I was able to get a neoprene cover same day as purchase)
Solid Build kind of a moot point. The samsung is built nice too.
Overall browsing seemed to be a little faster
Sense UI ... i kinda liked it over the TouchWiz UI.
Faster response, only cause the Vibrant is lagging a bit, for now.
Flash for the camera (Samsung is never going to live this down not having one on the Vibrant)
Suprisingly, Sprint's service came out about 10 dollars a month CHEAPER
Cons:
Horrible Battery Life. (Charge 2-3 times a day with regular use)
Heavy
Bulky, 4.3" screen is nice, but with the neoprene skin, this thing felt so big and heavy in my pocket.
Horrible Battery Life.
Got alot of dropped/interrupted calls on Sprint.
Slow 3G speeds.
And did I mention the horrible battery life? I had to manually turn off all of the antennas to even hope this phone would stay on half the day. 4G is basically useless because you'd have to turn it on or off when you wanted to use it to make sure it didn't kill your battery.
Vibrant:
Pros:
Lightweight & Thin!
Beautiful Screen
Much better battery life, I can make it through a whole day with normal use before I get down to about 30% battery life. This includes playing the SIMs once and a while.
Faster... on Quadrant, it scores much higher than the EVO did.
Faster 3G 3.5Mbps vs .5-.9 Mbps I'd get on the EVO.
I still have alot more to play around with.
But sadly, now with the things that are bugging me about the Vibrant.
Where's my Neoprene skin???
I already dropped and chipped the corner. *sigh*
Camera controls.... kind of harder to use than the Evo. Plus the preview screen doesn't auto-rotate pictures.... am I doing something wrong?
Lag - why does it lag when it's faster than the EVO?
GPS - was an issue, but fixed... should had been fixed before release.
The screen requires you to press a bit harder than the EVO did to get it to respond.
SIMs crashes on me alot when I'm redesigning the room or fish for too long. But that's a software thing.
Power Plug is at the top of the phone. Maybe this is to keep you from making calls while driving or having it plugged in... just seems weird to put it on the top. The little cover is nice, but on the top... really? Weird.
Now my biggest peeve with the Vibrant right now (and I hope they fix ASAP) :
COMPASS - This pisses me off. The compass is SOOOOOO slow. And it doesn't work all that well if you hold it almost straight up and down, which makes using applications like Google Skymaps USELESS. If you hold it above you the compass loses all direction. I really liked using Skymaps, I used it all the time with the EVO.
And because the Compass is messed up, it has trouble with the GPS, always thinking I'm going a different direction. I'll be sitting at a light and it will recalc and say to make a U turn cause it thinks I'm going the opposite way suddenly.
I'm really hoping they come out with some fixes for this stuff, otherwise... I might have to look for something else still. *sigh* I generally like this phone, but I've ended up playing around with it much more than the EVO cause I like the feel and look of it, plus I don't have to keep it plugged in all day long to mess with t.