Stating the obvious is the bugs even at Beta 2. The final touches I am sure i will fix many of the current issues but the colors they have chosen for the flat icons is not impressive. The extra white space that they have now chosen to incorporate into their IOS7 theme along with a thin font makes some areas harder to read.
For Example the Notes. Uses a white background with a yellow highlight. The yellow highlight does not provide enough of a contrast to clearly see the text at first glance.
The music player for Music is not a bad thing and I guess it will change in the future as how many songs it rotates through before it plays the same ones again. Maybe this is a current restriction on how many skips you can have but I am with iTunes Match so it should be as many as I would like or at least 10-20 per day. Also not a fan of the magenta/reddish buy now text/box.
Although I understand its a Beta 2 the messages after a little use just is a mess for the name of the people you are texting. The text begins to overlap and it just becomes a garbled mess of text and you can't make out the name of the person you are texting.
The recent calls history is too tall and the top of the history sits behind the all/missed calls box. I think this hasn't been adjusted for the iphone 4/4S vs the iPhone 5 screen sizes yet.
The list of incompatible apps is much larger than i expected and the crashes are also abundant. It's expected so I that is why it cannot be my daily driver but a spare iPhone 5 helps the processing of testing. Still like my HTC ONE and can't wait for the HTC ONE WP8 variant.
About to order the Lumia 925 but will wait to see what the US Variant will be like. Although most likely I won't use it on TMobile.
Using the Launcher 8 on the HTC ONE makes it realize that an 1080p WP8.1 phone would be great! Especially if they allow for a little customization like the Launcher 8
So Apple too the ideas of some old PalmOS, Android, Cydia Apps and WP flat ideas and made a little better mix of the idea. They have a long way to go to marry those ideas into a more cohesive OS.
Beta 3 coming soon