Ups: great photography, high quality paper stock, well-organized.
Downs: Limited focus, slightly dated info [2003 pub. date, so info is a good decade+ old by now (2011)], UK specific parts suppliers may or may not be still in business or available elsewhere.
This title is basically broken down by front & rear, with the focus on upgrades to the suspension & brakes. Not much in here otherwise, but the various options are presented in a "case study" format, so it has some appeal even if you aren't interested in doing such work yourself, just so you can speak knowledgeably with someone you hire to do the job.
I don't own a VW bus anymore, but have been suffering some nostalgia for my old Splittie, so the book was an interesting read for me, with its presentation of all the options of modifications I didn't have money for back in the day! So even if you're just interested in these old cars, it's worth checking out, altho' if you don't want to lower your VW bus, then there isn't much reason to buy it: most of the focus is on lowered "California look" VW Transporters [with only a small amount of info on raising them for the off-road set.]
So there you have it: other sources focus on the motor, this one is all about the springy bits.