ehh something must be wrong with your iphone 5, my iphone 5 beats my brother's note 2 in speed tests every single time
I've just tested side by side and for example stock apps like Calendar, Photos, Messages, App Store loads slower in comparison with their counterparts from galaxy s2 (with aokp custom ROM). And I have 1215 messages is the s2 while on the iphone 5 I have below 50. Plus the Contacts app loads on par, but on Android it shows also the profile images (have a lot of em).
Not to mention 3rdy-party apps which are loading slower, such us Twitter, Translate, etc.
One app that loads faster than on Android is Facebook. But still loads slow and tend to crash quite often.
Regarding of Android crashes, in more than 2 years I can say it's quite stable in this aspect. I got very few system apps crashes and there are apps that are poorly written and crash from time to time (or even at startup due incompatibility).
Apple doesn't announce the user directly of the crash, it just close the app and silently write a log. Maybe most of the people doesn't "know" that this is a crash..
And in 3-4 month of using iphone 5 got a few times more crashes than using Android for more than 2 years (rooted, stock or custom roms). But I can't blame iOS since most of the crashes were due several cydia tweaks..
In other words you cannot blame Android due 3rdparty apps crashing because of being poorly written as I cannot blame iOS because buggy apps
Some points are funny and pure marketing

. For example the section with retina display

). There are 1080p and 720p displays with better dpi.
And the section about a6 chip being not battery hungry.. Yeah right, tell that to 3d intensive games where the true power of the gpu is being put on work..
And to answer to the topic question

No, I won't leave iOS soon, just came into this from android. I like that the iphone 5 has better battery life (even with lower battery capacity) and I like that the whole UI is smooth in general. But I consider jailbreaking essential

Still missing some stuffs from Android (google apps, better battery information, processes viewer, bsplayer, etc)