Well Pat, it's like this.

Pro:
No climbing required.
Cheaper than a self supporting tower for the same windload rating.
Won't rust.

Cons:
Guys must be slackened to raise or lower a beam antenna. Not good on a windy day. Generally not good to climb on a windy day anyway so this might not be an issue.
If the rotator fails you may not be able to orient antenna to clear the tower structure.
Can't sidemount antennas for fixed orientation.
Can't use an antenna with elements spaced closer than the width of the tower. At least near the boom to mast mounting area.

I still have two antennas to mount. All that's up now are a VHF/UHF vertical and a VHF/UHF beam. After the holidays we'll mount the 6M and HF beams.