I use sipgate.de for access to the public phone system. I connect to them via asterisk which connects to some other PBXes and my devices. Whenever somebody calls my german line (or my extension at an other PBX), the call ends up in my asterisk. I try to ring my mobile first. If this is unsuccessful, I tell the caller via recording that I will try some other devices. If that fails, the caller can leave a voice mail and I get a notification via email. (xmpp soon..) My setup is still missing caller-id filtering fun, but it was easy to build and runs stable since a few month. If you have a server somewhere, perhaps a simple asterisk with a sip provider is all you need. I can't wait until I find a usable sip client that supports zrtp on my android. I have high hopes for jitsi. (https://jitsi.org/)

Twilio isn't bad but I didn't want an API and full programmatic control. Like you I just wanted out-of-the-box features that work. RingCentral gives you ability to have toll-free numbers, voicemail, call routing, call recording, office hours, fax (but no SMS). You can have up to 999 extensions (users) for no extra cost. If you have a cell or landline currently, RingCentral is pretty cheap because it forwards calls seamlessly and you don't pay for any minutes (and you can dial out from that external phone too, by initiating the call from their app which calls you first).

Dogfooding FTW!