[XPERIA X10 General] jerkysans:
Hi. This will also be long. LOL.

I own both an X10 and a Galaxy S. To summarize, I had the least frustration with my X10 than with my Galaxy S. Yep, I have two. Both unlocked. That's how things work in the Philippines. You would want to have a separate phone for work and play (personal stuff--like family and friends as our carriers here charge weirdly for their services).

I got my x10 first and I was very happy--lags were negligible and 2.1 really made it zippier. Twas my first Android and was on 1.6 and got updated to 2.1 like 3 days after I got it. Then my contract retention with the other carrier came up two weeks after and I picked up a Galaxy S. Initially, my Galaxy S was on 2.1 and it was OK save for some negligible lags but after a 2.2 upgrade, it kept freezing and dying, and Swype won't even let me write anything sensible. I was so frustrated to the point that I wanted to flush it down the toilet, if it wasn't so pricey. Then I applied a lag fix and it went all zippy and I'm happy with it.

Now for some real comparison

Galaxy S over X10

- faster operation (after the lag fix)

- way way better S-AMOLED screen, perfect for long movies

- pre-loaded apps like English Dictionary, Vlingo, Office Editor, File and Task Manager

- Multitouch (though the x10 will get one by March 31 2011--latest)

- cool slide out usb hatch

- front facing camera

- access to froyo (2.2)

- FM radio (not true for the captivate)

- in my case longer operating time than the x10, my x10 drinks juice

- notification pull down has remote control to wifi and others

- more possible to get updated to 2.3

- very light and easy to pocket

- better voice calls with or without headset

X10 over Galaxy S

- more eloquent UI / software tweaks (better animations, more premium feel)

- a lot better and stand out body design (IMO)

- three hardware buttons

- better 8MP camera

- better continuous autofocus (after 2.1)

- I love timescape over buddies online (samsung's own social media widget)

- more convenient location of lanyard eye (lanyards are important to me because I used to drop phones often)

- feels heavier and feels greater on hand thanks to the curves

- best sound (music, I mean) reproduction (IMO)

Galaxy Cons

- Soft keys (back button, and home if you are on captivate/vibrant) can take you out of what you are doing

- Less reliable operation due to lags and soft key back button issues

- Looks cheap, uninspired design

- TouchWiz UI sucks big time

- clunky messaging and contacts interface--shows less information at once due to big font sizes, probably useful for older people

- can't use samsung widgets when using launcher pro

- buggy because it's Samsung!

- low user interface quality check--you might be surprised to find poorly constructed and grammatically incorrect sentences on the Galaxy S's UI, thank God by 2.2 most have vanished

- Samsung Kies (syncing software) sucks

X10 Cons

- plastic usb flap cover

- poor photolight does not help night shots, in fact blinds people you are taking pictures of

- kind of laggy due to timescape, but I can live with this

- mediascape is kind of old-world and hard to use, best use poweramp / winamp

- pre-loaded apps don't add much value

- stuck at 2.1 for the foreseeable future, probably forever

- does not have much faster ROMS available due to the bootloader not being cracked yet

- poor voice calls experience until you wear a headset

So mostly X10 wins over the Galaxy S on the hardware design bits and on the custom UI bits. Galaxy S, however, is overall better in performance after the lag fix. But if you are too scared to do it, you will be stuck with a laggy and freezing FROYO phone. It might even die on you. It's all a matter of finding what you can live with and without and then picking that one. I haven't had any MOTOROLA ANDROID phone, but DROID 2 Global sounds nice, but it's bound to be heavier. Good luck on the choosing. As for me, I'm stuck to these 2 for two years. LOL.