crap, last night charge 10 100%, wake up and found out my battery drop to 60% due to wifi sharing and i NEVER on my wifi connection...heard it's a bug for Android 2.3.3..hope to get a fix soon..

wuu.. metal backcase... 

This has been mentioned so many times that if this question popup 1 time and I get a RM10 , I should b able to get a SME SGSII now ........ Yes , its duo core , its gonna b hotter than any single core

We all SGS2 user will experience the same as what you are now....Dual Core technology will create and generate HEAT so it is just normal bro. The technology itself is build for that type of situation, so be no worries.
Just for your information....last few weeks when i'm using the SGS2 (oversea set)....i faced a very rare overheat feeling, and it is toooooooo dammmmmmmmm HOT came out from the phone when the phone itself hung at loading some high end games (can't remember what is the game) .....but then i realize that, from my experience with electronic items, sometimes it needs to be stressed up but not too much (a.k.a burntest).
Around 3mins with hanging condition after that i decide to kill process and reboot it.....and then you know what, after the incident and till now i experience that my phone is working SUPERBLY HELL SMOOTHS SPEED and DARN MORE EFFICIENT.....thank god for that. And now i'm very2 satisfied with these product. 

Maybe i just got lucky

what you can do is either register online or just send in the warranty card. Make sure you get the shop to stamp it first.

Did you clear cache? How long did you use your phone? If it's a hardware defect and get it change 1-to-1 fast...

Hmmmm...are u sure? i am on stock rom.. i have taken up 8 gb on songs and video's..dont ask about the messages. and its still working fine.
Maybe u could do a hard reset. mite be bugs as u said..
The ROM just alters the config of the hp to remove the unnecessary stuff..
WELL thats what i think..lol

Honestly I never encounter this problem of yours. You does sound like quite frustrated with android. So you from apple? /gg

Check on your Apps. Sometime Apps causes it. I have over 30 Apps now but my phone is rocking even before I root.

@un_id

not all android phones have to root only can use. it just depends, my gf htc desire 1 year ad never root never give her any problem.

I also feel very lag. But i know that's because of touchwiz, everytime when i want to go back to home screen, it takes me around 1 or 2 sec. So I just install launcherpro and ditch the touchwiz. now it's like butter.

Yes, you did expect too much. Go use an Ipad 2 for a while. IMHO it HAS it's laggy points, which shouldn't even happen supposedly.

BUT, IT SHOULDN'T BE LAGGY ALL THE TIME. If it is, something's wrong.
Better yes. Wayyyyy better? Android, and most of it's apps ARE NOT QUITE dual-core optimized yet, really. And the stock browser is crap to tell you the truth. Get something else.

And again, about lag, it should have it's laggy points, but should be smooth generally. Android IS NOT GPU ACCELERATED, so it will NEVER be as smooth as the i4. At least not on Gingerbread.
Do try hard resetting. If it's still laggy most of the time, either something IS wrong or everything is simply not smooth enough for your preference. And do go try comparo with somebody else with a stock SGS2.

And actually, to tell you the truth, the i4 might seem smooth and quick, but is in truth quite slow. I ran my i4 back in the day with fakeclockup - faster animations - and my i4 will more often than not take it's sweet time after the transition animations (app launch) have finished to launch whatever I tapped on.

Apple hides the slowness of the OS behind those smooth and extended transition animations. Clever and devious.

i guess it's because the procrssor aren't running full speed all the time? so it will lag abit when running at lowest speed to save battery and suddenly we 1 finger touch already want it to respond and process thing more than the lower speed can go smooth...

Using app killers and freeing up RAM isn't really necessary, nor good, for android phones.

This is one of the many articles about this. Read up a bit.

To un_id, what I'd do if I were in your shoes would be to check on the CPU usage of your device. You may have a badly coded app hogging up CPU cycles, thus the lag you feel. I personally had only a week experience on stock ROM, but I felt no lag during that period of time, except when I had one homescreen page that had the youtube app, news app etc on it. Too much animation on that page, plus my Sakura Falling livewallpaper I think. Even then mine was rooted and I used Titanium Backup to freeze a bunch of Samsung apps that I had no use for.