I have the BMW Workshop manual, the ETM (Electrical Troubleshooting Manual), the Haynes manual for the 3/5-series, and a BMW Torque Spec manual. I also had the Bentley manual for a short while but sold it. My opinions:

The workshop manual is the most comprehensive but does not contain much descriptive text for the maintenance procedures. It probably assumes that the reader has attended BMW technical training but I find that if you follow the instructions exactly as described you can do the job. My one complaint is that the manual does not contain torque specs or filling capacities.

The ETM is year-specific and one of the best- written and best-organized manuals I have read (all manuals, not just car manuals). It covers each electrical circuit in great detail, gives photographs of each component, gives diagrams of the pin-outs of each connector, and even describes how to troubleshoot circuits. This is by far the most relevant manual and is invaluable for the E32.

The Haynes manual is a cheap alternative to either the workshop manual or the Bentley. The majority of the major mechanical components of the E34 535i are common to the E32 735i. I often use the Haynes in conjunction with the workshop manual since the Haynes contains more narrative and describes home-made alternatives to the factory tools.

The torque spec manual covers all BMWs from 1980 to the E31/E32/E34. As the name implies, its sole purpose is the torque specs for just about every nut, bolt, and screw.

Lastly, the Bentley manual. I simply did not find this as useful as the workshop manual and, since it didn't provide any additional information, I sold it. In fact, I compared one or two maintenance operations from the workshop manual and found the Bentley to be lacking.

Hope this helps

Alex

I consider myself with fairly good mechanical skills and I truly believe that the Bentley is a good reference, but it really leaves to ones immagination many steps on repairing/dissasemblying. For example, check Bentley on how to remove the AC/heater control panel in the console. Does it really tells you to push in a retainer in the right side to push it out???? Noooooooo, and you'll break the retainer if you attempt to push it out without doing this. Of course in the country of the blind the guy with one eye is the king! That's really what happens with Bentley's, when compared to Haynes or his competitor.
This is my first BMW, but I have have several american cars shop manual very well done. I have been tempted to buy the real BMW shop manual that sells for $120 plus $ 75 for the electrical diagrams. I haven't seen that material, but I suspect that it is a heck better than Bentley.
Is there anyone here who have the aforementined BMW shop manual?????

The Bentley is a must, ESPECIALLY for non-mechanics. You can do more damage in one try without the Bentley than twice its cost!

It is woefully inadequate for the heater/a.c. system, but don't feel bad. Most BMW dealers can't fix the damn thing either (though they will charge a lot trying).

Bob