Hi Guys here are some of my findings with Lumia 1020 cyan+update1 dp hope it will be helpful, to improved ms os.
WP8.1 Update 1 Findings
App Corner
Don't bother to organized your tile at the app corner because you are just wasting your time and effort, after all, the sweat you have done to make your app corner look pleasant to your borrower is useless, the next time you launch it to impress your friends,it will return into its messy and clutter arrangement.$ frustrated man

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Wi-Fi
Wi-Fi means so much in every smartphones, how come it is connected to the Wi-Fi but says no internet connection(sucks), while upon checking with my other devices they are sound and well connected. You have to manually off and on your Wi-Fi to connect again and again and again....

in addition to that, Wi-Fi connection turned weaker than the previous os version.
What the he'll once you wake up and scroll your start screen after a long sleep(meaning phone is lock for a couple of hour) it lag like a he'll. what happened with its smooth and water like touch screen sensitivity. Seriously! bring back the joy of soft/smooth touch and scrolling.(happened for second time)
Bluetooth
Once you've start sharing files over Bluetooth you should expect the following:
*Unable to connect with the internet
*Can't used your app properly
* app that requires internet connection will turn useless until sharing is complete or until you soft reset your phone.
Found a bug on my start screen jeez... Bug bug bug hate it.. Pining lots of tiles on your start screen will give you so much of bug.
Wifi connectivity not so stable.
While i was surfing over my Lumia IE11, i received a notification, so i immediately swipe down my lovely notification center, then i noticed that the Wifi icon says no internet connection while i keep receiving new notifications from fb, tweeter and other app. Will i say my Wifi indicator is a liar.?