turnip

Been a customer of aptela for 5 years now.  As for hosted business PBX solutions they where one of the first vendors in this market space.  For the first year there was a hiccup from time to time but but never anything resulting in a total outage that lasted more than the time it took to reboot a server.   In the past 3 years I cannot remember any specific issue that was there fault.  We had some fiber cut that resulted in our office having outage but that was a cogent issue.  We just rerouted the calls to our cells through Aptela's easy to use dashboard which does work on Android.  Also, adding and removing lines takes no time at all.    
Understanding the technology is key.  I recommend anyone that is going to use a hosted PBX solution for your business to analyze there broadband needs prior to implementing any internet based phone solution.  Bandwidth is key and if you have lots of PCs and Phones on the same network you could at any time saturate the network causing packet loss which will result in poor call quality.  This is your responsibility not the vendors.  Honestly we have had more issues with our ISPs than Aptela.  
I would recommend as a MUST to anyone that is on the go and needs to stay connected.   Being able to have multiple phones in two locations that ring at the same time along with the find me options is truly a blessing if you travel.   Knowing immediately if you missed a call or have voicemail because of the email notification features is amazing.