When you ask the question "are you satisfied with the precision and reliability", it really depends what your expectations and end use requirements are, especially with regard to rigidity in pitch roll and yaw between the moving carriage and the mounting rail. This goes hand in hand with the damping characteristics if you are building a machine tool.
For a simple, fairly accurate positioning system with a wide range of travel (including turns) for production line automation and low force "Pick and Place" devices you will be pleased with the grooved cam follower type vee wheel on special section rail. Fairly short sraight systems are OK with plain or ball bushings on ground shafting, but you must mount the shafts very accurately if you use a pair to eliminate rotation. Most Telescopic systems I've encountered are little better than kitchen drawer runners.
For ultimate machine tool type rigidity and accuracy, then the best (and most expensive option) is recirculating ball and roller carriages (preferably caged type) on precision ground rails, although they won't have the ultimate damping effect of a prismatic dovetal slide they give smooth movement that is free from "stick-slip". With all types of guide, pay careful attention to the aspect ratio between the guiding element mounting points and the force vectors you expect to encounter to minimise deflection.
Hope this helps.
Trevor Clarke. (R & D) Scientific Instruments.Somerset. UK
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