Not to take anything away from Mercians, but Bob Jacksons are full custom -- and that includes paint and graphics. If you like a particular paint scheme, decals or color combination, I'm sure BJ could do it. Send them an email. I have seen some BJs with stunning paint jobs. In comparing BJs with Mercians, I lean toward the Jacksons because their geometry suits me better and prices are less (including modifications that are considered non-standard).

Another thing is that the Jackson touring frame is clearly designed for touring. The comparable Mercian frame (King of Mercia) is a compromise and more of a sport touring frame. The Jackson frame has details such as stouter tubing, longer chain stays, relaxed angles, eyelets for racks and fenders, and optional cantilever brakes that are designed for touring. You might be able to get these modifications to a Mercian frame, but you would probably pay for each change while they are standard or no-cost options with the Jacksons.