One way to do this is to go to the LDP site http://www.linuxdoc.org click on HOWTOs and then compare the sources of the same HOWTO in the two formats: LinuxDoc and DocBook. The DocBook tags are often longer than the equivalent LinuxDoc tags and there are sometimes more of them needed to do the same task. DocBook uses <para> and </para> tags to enclose each paragraph while LinuxDoc uses only a blank line to separate paragraphs (no tags). To emphasize the word "release" the comparison is:
<emphasis>release</emphasis> release <em>release</em>
Yes, you have to type release twice in DocBook. For a section start:
<sect> <title>Introduction<title> <sect> Introduction
So there's much more to type with DocBook if you're typing in tags manually. But DocBook has all sorts of tags that don't exist in LinuxDoc so it's more advanced. Just using a subset of DocBook doesn't help as you can see from the above examples. There is still a lot more tag clutter. With a more and longer tags the document becomes harder to read unless you use an editor that hides them. But hiding them has it's drawbacks since it's nice to see what tags you've used.
Still, the number of people who use DocBook greatly exceeds the number using LinuxDoc. But if you do decide to migrate to DocBook there's a program by Reuben Thomas (ld2db) which can help make the conversion. It's not 100% perfect and you may have to do some manual editing. The LDP also automatically converts a LinuxDoc HOWTO to DocBook after you submit it.