If you're projecting a 1080p image onto a 204.8mm x 153.6mm (~ 8" x 6"), you end up with an image that is about 1440x1080 pixels.  The pixel density is approximately 180 pixels/inch, or about 7 pixels/mm, so that would translate into a dot of about 143nm (microns).

Hence their claim of only 200nm X/Y precision.  If you were to reduce the size of the projection (therefore the size of your build) to 5.5" x 4", then you would get ~100nm dots (technically 94nm).

The precision on other resin type printers like the FormLabs, is given by the size of the UV laser dot, and the precision of the mechanics.  I don't know if it uses mirrors, or some sort of X/Y moving gantry, but there are mechanics involved.

On a DLP, to achieve superior resolution, you'd probably have to look for a higher resolution DLP chip, like maybe a 4K.  The bottleneck then, becomes the quality of the resin.

We are now kindly inviting everyone to finish a survey for us.

We are now developing the next generation of our DLP 3D printer, and we really need to gather some opinions before it hits Kickstarter. It will be a DLP printer with the largest build volume on the market, and it will provide the best solution to SME, MakerSpace and personal users.

There will be only 8 questions, and every member will be notified before we launched to make sure that every one gets the Early Bird reward if you are interested(remember to submit to our newsletter).

You can find detailed information including tech specs and test prints by visiting our demo website(which is free, and will be reconstructed later): http://futuremake3d.wix.com/rocko3d

Demo videos are coming soon, please stay tuned. The survey is on the "More" page, so help us get some feedback.

Thanks!