Did you find any that work well? Any implementation?

Partially implemented SMS Magic. It is a good solution out of the box, but I want to Skuidify it which takes a little extra. Viewing the history of incoming and outgoing is pretty easy in Skuid, but sending a new message required some Javascript. Twilio is another good option if you want to build the entire interface from scratch using their Salesforce API Library.

Thank you for sharing this.