Dolphin Guides- an all-in-one linear guide system

I am wondering if anyone has had any experience with Pacific
Bearings "Dolphin Guides".These are two piece linear guides that
could greatly simplify the task of building cnc systems.

The down side is the price, of course. I estimate the cost to be
about double the cost of constructing linear ways out of separate
components. But for people like me, with limited equipment and
knowledge about machining, it certainly seems like an attractive
solution. I should add, Dolphin Guides are still cheaper than the
other all-in-one linear guide systems that I have seen.

I wonder if these guides are accurate enough for precise machining.
They seem to use the same materials as the other Pacific
Bearings "Simplicity" products, which are ceramic-coated aluminum
shafts and Frelon-lined bearings. The "Simplicity" line is listed as
having class "L" tolerance, I think. Can anyone tell me what that
means?

They can be seen at www.dolphinguides.com
Prices are available at www.mcmaster.com
Cut and paste this >>> twin-shaft frelon-lined guide and rail <<<
into the search box.