Let's run down the scenario....
You are contacted by a client with a 3,000-5,000 square foot office area populated with cubicle partitions.

You are asked specifically to dig up some info and options on a masking system

On 1257383360, phil said...
Has anybody done this and has it worked? Any pitfalls? Complaints from the workers?

for this task, you had this advice for the client:
1) to turn the PCs on

2) to have the HVAC system fan set to run full time

3) to offer the employees the option of wearing headphones and playing their own music while at work

4) to move the loud employees to the other side of the office

So anyway....
Thanks for participating in one of the internet's best CI resources.

In my last job I made pizza.

Not really. This is what I was commenting on as part of the original post:

I conveyed my experience as one of those "workers." Is it expert opinion of an installer? No, I didn't say I had installed anything. I was very clear on the issue that was bothering to me, i.e. trying to understand someone else talking to me. I appreciate that the noise does mask other sounds and did not disagree with that.
The above suggestions come from experience. In my last job I had over 1000 people reporting to me. Prior to that, collectively I had probably another 1000 people working in my group in half a dozen companies. Trust me, I have heard every complaint there is from engineers regarding noise.

Making sure people who use phones a lot or bang on the keyboard have their own office or placed away from others is a more effective solution than dumping more noise in the office to try to drown them out. My motto is to always, always, try to fix the cause before dealing with the symptoms!

With that said, I do see that others have had more positive experience with masking and I am sure OP is taking that into account in addition to anything I have had to say.

It is a great place indeed. I suspect what makes it great though is the exchange of differing opinions from people with different experiences, especially in matters dealing with subjective things like sound and noise :).

Now that we have established that you play Calvinball, lets carry on.

Sorry guys, didn't mean to imply any sense of superiority in that comment....

Calvin: "Dad, are you vicariously living through me in the hope that my accomplishments will validate your mediocre life and in some way compensate for all of the opportunities you botched?"

Father: "If I were, you can bet I'd be re-evaluating my strategy."

Calvin, later to his mother: "Mom, Dad keeps insulting me."

Hopefully all of these conversations are in good fun and learning, as the above episodes were. :)

8) mandatory ball gags and mittens for everyone in the cube farm.

I have my very own "system"...

The voices are always there.....