Patiently waiting for this to be available in the US at Best Buy. I'm still having an internal debate on whether to get the A55 or the A105. I'm upgrading from the A20 so either one would be a substantial upgrade.
Pros for the A55 for me is: The Battery Life, The newer sound enhancements, the new interface and new simple UI. The cons however is that it doesn't have native Podcast support like the A20 (seriously, you just needed to add one more tab Sony!), STILL using the WM port, although that isn't too big of a deal, it's still bothersome and unnecesary and the buttons don't look as nice as the A105.
As for the A105, the pros are: Android based, so other music apps, specifically Primephonic can be used without the need of the Bluetooth receiver, more flexibility in the UI, snappier UI, from what I can tell it sounds better than the A55 (some can back this up for me hopefully), while native support of podcasts still isn't there, it has Spotify and I can load podcasts using that or an external podcast app from the Playstore, USB C!. Cons: Since it's running on Android the battery life is going to be significantly worse that the A55, significantly more expensive than the A55, worried that the OS will get bogged down more and more as time goes by (this happened with my old F series Android walkman).