The Monolith can be used with BOTH the mic boom and music rack from the Z series (references Z-728, Z-732 ). I own all of them and it's a super stable setup. I prefer this stand to a double X stand, like the Quiklok QL-641, which I also own. More stable, and more advanced concept. Only weaknesses: the weight (the price to pay...) and the system which was chosen for changing the position in height - not very practical, but solid. I use the Monolith for most of my long gigs (private parties, weddings), which represent most of my jobs.

I agree that for a quick gig an X stand may be preferable (a simple X stand will take less space in the trunk of the car). I use a T-10 with second tier (for the Ketron module) and have the accessories (mic boom and music rack) but I don't recommend to use them together, even with light keyboards, 'cause the stability is very poor: to the point of beeing dangerous for your equipment.

No experience with Apex stands whatsoever.

-- José.