I'm currently a Samsung Galaxy S2 user and am looking for a change and to get off Android. My initial thought was to get a Jolla phone but being in the US on T-mobile I'm not sure that the current Jolla phone is going to work and really be suitable so I'm considering the N9 as a stop gap until something else comes along.

My concern is that the N9 is not going to fulfil my daily needs which apart from phone calls and text messaging include e-mail (multiple accounts), multiple calendars and contacts syncing to my caldav and carddav server, the ability to make calls over SIP, Firefox browser, maps and navigation. I'm not bothered about social media and can forgo the other apps I use on my Android device.

I've done some reading and the N9 seems to be able to cope with my needs apart from potential issues with the caldav and carddav syncing. Has anyone got this working reliably?

What is the general reliability of the phone like?
Are there any issues with the usb port breaking or stop working?
Will it seem or feel slower than my Galaxy S2?

Is there any reason not to get the N9?

For around $250 it seems a good deal if it performs well. Where is the best place to purchase a N9 in the US? Amazon?

I'd appreciate any advice or opinions.