The 1/40th scale Orguss is one of the more common toys. It can transform into four modes: Humanoid (Orgroid), Tank, Gerwalk and Flyer. It includes a detailed cockpit with removable canopy and pilot figure.
A more difficult toy to obtain, the Olson Special is similar to the standard Orguss, but features a robin's-egg-blue color scheme. Its head and legs are slightly different as well.
There are actually two 1/40th scale Nikick toys: the standard 1/40th Nikick and the 1/40 scale Nikick Mass Production version.
The standard 1/40th scale Nikick is a well-designed piece, but apparently not well liked due to it's odd color scheme. It transforms into three modes: Humanoid, Gerwalk, and Flyer. It also has a detailed cockpit, but the canopy is not removable.
Apparently many people are unaware of the existence of this piece (I was), and it is even more difficult to find than the 1/48th Olson Special Orguss. The Mass Production Nikick has a different head than the standard Nikick. It also features a different color scheme.