As "perfectionists", we tend to expect paying more will obtain perfection. Two of the greatest benefits of the Oehler system, to me, are:

1 - The description of EXPECTED accuracy (they don't claim to be perfect). and
2 - the ability to control the accuracy of your system.

The system lets you set it up whatever way works best for you. Longer spacings are more accurate...and less convenient. I've played around with spacings as long as 18'. I have heard of one shooter that setup a 40' spacing. The 35P lets you go to 15'.

Most of my work is done with 9' or 8' spacings.

I would not put much faith in any chronograph that had a 1' or 2' spacing.

From the Oehler 35P manual:

ACCURACY:
The expected error on any one shot depends on both velocity and screen
spacing. Typical errors are shown in the table. The table assumes good light
conditions, dark bullets, exact screen spacing, and shooting through the
center of the Skyscreen III window. Actual errors under your shooting
conditions will be reliably indicated by the PROOF CHANNEL®.

1 FT 2 FT 4 FT 8 FT
1000 FPS 5 fps 3 fps 1 fps 1 fps
2000 FPS 10 fps 5 fps 3 fps 2 fps
3000 FPS 16 fps 8 fps 4 fps 2 fps
4000 FPS 21 fps 10 fps 5 fps 3 fps

You will typically see the above errors as differences between the primary
and proof channels of a Model 35P as you shoot under "normal" conditions.
PROOF CHANNEL®:


The system alerts you with a flashing display and printed asterisk if there is a
significant difference between the two velocity readings. Differences which
trigger the alert are shown for typical velocities and screen spacings.

1 FT 2 FT 4 FT 8 FT
1000 FPS 42 fps 21 fps 10 fps 5 fps
2000 FPS 83 fps 42 fps 21 fps 10 fps
3000 FPS 125 fps 63 fps 31 fps 16 fps
4000 FPS 166 fps 83 fps 42 fps 21 fps

I expect the above errors from THE BEST sensors. Assuming all other machines use the same quality sensors (probably being overly generous here), they should also have the same expected error.

For my situation, the "hassle" of an 8' spacing is well worth the increase in accuracy.

The Oehler 35P manual is available online. It is well worth the read even if you don't plan to purchase one. Additionally, you can find Bryan Litz's chapter on chronographs online. It is the best explanation I have seen of how chronographs work.