After watching the Pulse printer from MatterHackers go through a number of prints I thought the Z frame wobbled quite a bit compared to other printers. I saw this happening even at fairly slow print speeds.
Just as an experiment I decided to try and secure the Z frame during printing with a custom bracket (3D Printed of course).
I essentially stabilized the Z frame by attaching the bracket to a nearby stable shelf. The plastic on the right of the bracket between the shelf is just a shim to get it as stable as possible. The bracket is then screwed into the shelf.
The resulting prints are significantly better. The picture below has two prints from the Pulse that use the exact same gcode and filament. One is with the bracket (left) and the other is without the bracket (right).
You can see the worst of the layer shifts are significantly better, and in some cases they completely disappear.
I think other cartesian printers mitigate this issue by securing the power supply to the Z and Y frame, but because the Pulse has an unattached power supply (which is great for enclosure printing) the Z frame reacts more to movement. The Pulse has the filament spool holder in the place other printers might have a power supply, but it does not seem to provide enough stability, especially with tall and thin prints.
If you have a similar setup you are welcome to download the STL file and customize it for your needs: