I'm trying to decide between profile rails (LGR20) and round-supported shaft (SBR20). When I priced out my build (about 36"x56", using 80/20 1530 and 1545) I can save about $370 using the round linear supported shaft. Here's the lowest respective prices I found:

Round Supported Linear Shaft:
- 2x SBR20 (1500mm) + 4x SBR20UU bearing blocks = $170 (probotix for the rails, Keiling for the blocks)
- 2x SBR20 (1000mm) + 4x SBR20UU bearing blocks = $167 (Keiling)

Profile Rails:
- 2x LGR20 Hiwin rails (1400mm) + 4x LGW20HAZ0H/E1 Bearing blocks = $384 (Automation Overstock)
- 2x LGR20 Hiwin Rails (1000mm) + 4x LGW20HAZ0H/E1 Bearing blocks = $322

So that's a savings of about $370. I'm estimating the total build will come out to around $4500, so I'm already in for a bundle and trying to save where possible.

- Would I get more bang-for-the-buck spending that money on other components?
- How much more accurate are the profile rails going to be?
- I've heard they are much more sensitive to racking, is this true? (I'll be using a single ballscrew under the table for the X-axis.) WouldI need two ballscrews if I go with the profile rails?

Thanks