I am a freelance firmware developer/consultant, specialising in interfacing, control and communication with embedded microcontrollers - with particular experience in GSM/GPRS & M2M applications: http://www.antronics.co.uk/services.htm
Clients have ranged from big-names like BT to small, local start-ups: http://www.antronics.co.uk/portfolio
My first encounter with Open-AT was in 2005 with an M2M vending machine project. The client was seeking a ready-to-use hardware platform which could accommodate a custom firmware application for the vending requirement. After researching the available platforms on the market, I identified the Wavecom Fastrack M1306B (as it then was) and Open-AT. The rest, as they say, is history. The resulting units are now installed in over 500 vending machines across the UK - using both the orignal Fastrack M1306B and its replacement, the Fastrack Supreme.
Since then, I have been involved with many Open-AT projects using the Fastrack series (M1306B, Supreme, Xtend), Q26, and WMP100 in fields such as energy monitoring, RFID, vehicle & people tracking, Biometrics, etc.
As well as Open-AT, I also continue to be involved in more "traditional" projects using GSM devices (from Sierra Wireless and others) just as "dumb" modems - and microcontroller projects with no GSM content at all.