Mostly I love it - I have to confess to being generally unimpressed with 'iTunes' and 'iPhone' type interfaces - and no matter what you say the WP7 stuff is similar - but I'm getting used to it.
Phone is nice to hold, great screen, touch is mostly very responsive.
The USB jack is not a 'standard' mini USB - so I need to get new chargers etc (why can't they just keep to a standard size?)
No custom ringtones! I know this may not be critical to many people, but I like my Star Wars ringtone - it's how I know it's my phone that's ringing and I've been using it for years (since my first SPV!). What happened to 'Always Delightful and Wonderfully Yours' ?? - Yes I love the way you can customise the home screen (live tiles) - but I want my ring tone back! I'm hoping this will come in a future update....
I've had some instances of the screen not being as responsive as I'd expect - but that's partly me getting used to the interface. I have noticed a lack of consistency in some places - some onscreen buttons are clearly buttons, but others are just text. I do tend to find myself tapping on words to see if they do anything; it's not always obvious.
The standard phone icons (battery, signal strength etc) automatically hide and you have to tap the top of the screen to see them. I work in a crap reception area so I need to keep tabs on signal strength, so I'd rather have the icons on display.
I've started downloading a few free apps - had one that wouldnt work (the Messenger app), and one that said it wasn't compatible with my device (which was funny as it was an HTC app I was trying!). But others have downloaded fine with no issues.
Overall I'm pleased - it's early days, and I haven't really started scratching the surface yet, but it's a damn good phone and a damn good operating system.
Anyone else got any thoughts yet?