The Daltech is, far and away, the most common announce box I see in the field. Reliable and built like a brick outhouse.
HBO Boxing went from those to the Studio Tech 233's for a bit (their lead A2 hated them), but have since switched to the Lance Design ADX-120's. It's an interesting system that uses Cobranet (audio over standard TCP/IP) with dedicated hardware to address the needs (Local comms and IFB power, etc) of the broadcast market. A fiber connected network switch is used to link the system back to the truck outside.
Riedel also has a great panel, but as the majority of the major OB trucks here use RTS systems instead of Artist, it doesn't offer much of an advantage.