I teach hand cut dovetails and provide tools for the students to use. One tool is the marking gauge and the one that most people like is the Tite-Mark by Kevin Drake. But at $90 each - and I recommend that they have two for dovetails - it's an expensive tool to bite off on.
Recently I found a marking gauge by Taylor Tools on Amazon that appears to have the same ease of use as the Tite-Mark so I ordered one to check it out. It's operates the same as the Tite-Mark so you can do one hand adjustments. And the cutter is the same size and with the same screw threads as the Tite-Mark so if you break the cutter, you can replace it with one ordered from Kevin Drake.
It sells for $30 so you can buy two for less than one Tite-Mark.
The fit and finish is not as good as the Tite-Mark but it works fine.
Here's a couple of pictures. The Taylor version is at the top and the Tite-Mark is on the bottom.
Looking at them from the end, the Taylor is on the right and the Tite-Mark on the left.
I haven't used it much yet but it seems to work fine.