I've been doing you all a great injustice by not covering this line for you on CDX. It's tough though because once my boys get their hands on them, they are torn apart and re-assembled many times over, the packaging nowhere to be seen.
The whole idea of Mega Rigs is that they are modular vehicles. Each piece has connection points that can be attached in any number of ways. Each year has a theme, and this year its Pirates. Last years space theme was awesome, and all the parts from any previous year can be used with any new set. This has been going on for years now, and they all still work together, unlike other toy lines (ahem.. Imaginext). The figures that are included are about the same size as M.A.S.K. figures or Starcom figures, and the building system is similar to the hexagonal joint system used on Robotix.
What really floors me though is the continued attention to detail that these toys exhibit. Its as if the designers are throwing in Easter eggs for adult collectors. For example, the Shark Ship set has small barnacles, starfish and other details etched into corners underneath the toy. The Shark itself has an opening belly (like the Star Wars Tauntaun) that features detail INSIDE the shark, like a ribcage, license plate, and even a kitchen sink.
This years pirate theme is based off of the Shark Ship, but it looks like an entirely new mold. The suction cup action on the additional play set is also very cool.
Did I mention that they all have tons of missile firing action?