PS2 is most powerful current generation console in vertex shader power due to two programmable vector units at 300mhz but much optimization needed since unusual architecture. Highest polygon count in a game is 20M/s, which at 60fps is 333,000 polygons/frame, at 30fps is 666,000 polygons/frame.
To give you idea of how much polygons it is, highest polygon scene in Far Cry PC version = 500,000 polygon/frame on maximum detail! If more optimized PS2 can perform even better and because fully programmable, more effects can be done to vertices than normal vertex shaders. Also now developers learning to do normal-mapping, a type of spherical harminic lighting, sub-surface scattering, HDR, etc... all on PS2! Only problem is it might be too late for a lot of PS2 games with all these effects since next-gen already coming up.