I personally don't see much of a difference between the OSes in terms of lag. I know there is a meme that iOS doesn't lag but my iPad lags all the time (and always has). If I do a big sync I have to restart the device because it's unusably laggy. My Nexus One with Gingerbread rarely lags at all.

* I don't really like Android that much (or iOS).

I think that there's selection bias at work. I have an android phone, but test software for a company that only has an app for iphone (owner is iphone fan). As a result, I have to frequently borrow other people's iphones to test things with the app - and I find that the amount of missed swipes, jitteriness and responsiveness is very similar between the iphone and my 'lowly' motorola defy. If I have a lot of crap running on the defy, it performs worse, but in normal use, I don't find the touchscreen responsiveness much different between these phones.

To be honest though, I'm running CM7 and not the stock image. Still, I see iphone/pad users miss swipes all the time or have to try repinching a few times, but for some reason it registers less on a shiny device.

Dead right on this. The big 2 complaints I hear from iOS to Android users are the stutter and app/content discoverability. Google should be able to plug both of these gaps though and if this release doesn't do it they stand to lose a lot to forked implementations like Amazon's.

New Android update next week though. Is it just me or did they really miss a golden opportunity to go head to head before people pre-order 4GS's this week. Google should have counterprogrammed their event for tomorrow.

Android was designed when mobile GPUs were an oddity and stylus input was the norm. As such, rendering is mostly done in software and both redraw events and input are handled by the CPU. Mango and iOS were designed with hardware acceleration in mind, and render everything to 3D textures so they can use the GPU to get that smooth feel.

The ICS reveal later this month will reveal whether Google has addressed this issue. Most of Honeycomb is already GPU-accelerated, but not all of the performance issues were fixed.

    > The iOS and Mango device respond very similarly to
    > basic things like swipes, pinches, etc... Android 
    > is a lot more jittery, even on the SGII HW. 

Before I ditched my iPhone 3G for an Atrix, the device was barely usable. It didn't just stutter, it would hang for upwards of a minute when opening certain apps (maps, I'm looking at you), and it's not like the device was defective as I've used others and had an identical experience.

Now, maybe the 4G offers a smoother experience than Android (no GC + hardware acceleration?), I don't know, but the 3G experience was sure as hell nothing to write home about. I can say, however, that my Atrix is noticeably more responsive after switching from Motorola's firmware to Cynanogen Mod, but -- again -- I don't know how it compares to a 4G.

iPhone 3G came out in 2008 - nice, because it was new - but yes, had lots of lag - better than the competition (at the time). 3GS gave it a bit of a boost. iPhone 4 was the first (in my experience) iPhone to significantly reduce lag/latency in most areas - the shutter speed was it's achilles heel (it sucks). I'm upgrading to the 4S for one reason only - Supposed zero shutter lag.

perhaps try the camera out in a story before forking over the cash first :)