Noise and cab size
The drive works by moving air, so the elevator makes an audible sound while the cab travels; ask to hear a running unit before deciding. Cab size is fixed by the tube diameter, so it cannot grow later, and a round cab leaves less usable floor than a square one of the same width.
Sun and placement
A clear tube beside a large west-facing window can warm up on a Texas afternoon. Placing it away from strong direct sun, or planning shades for that window, keeps the cab comfortable.
Power outages
Manufacturers handle a power cut in their own ways. Ask how the cab gets down, whether it can be lowered from inside, and whether a backup is included, and have the answers written into the handover papers.