I've been working on hexapods and delta robots for a while...
[nomedia="http://www.youtube.com/watch?v=bQtT4EDyQVU"]YouTube - Delta Tau's Brick controlled Hexapod[/nomedia]
the video above is a hexapod with magnetic joints, and I made it for @$15k. I made it for Delta Tau, and they travel with it to shows including IMTS etc... along with my little mini deltas that people like so much.
[nomedia="http://www.youtube.com/watch?v=Gv5B63HeF1E"]YouTube - Mini Delta Robot with background noise to verify actual speed[/nomedia]
These are some very capable machines, but you will find some gotchas in controls, beyond complex kinematics with multiple solutions, some of my biggest challenges were in precision calibration required due to mechanical imperfections. Try tracking a small error due to math or mechanics.... not fun. Also remember that the hexapod is rigidly coupled so good, stiff, powerful actuators must be perfectly coordinated or they will crash the hell out of the machine... so start off with mush tuning or suffer the expensive consequences.... or use magnetic joints... (God bless Sina at Delta Tau for that idea!) Actuator error from the upside down hanging, magnetically joined hexapod in the video only resulted in a dropped end effector or actuator.
Fun stuff tho!
[nomedia="http://www.youtube.com/watch?v=lkbFCVcRP88"]YouTube - Fast 140ppm mid sized delta robot[/nomedia]