The real fork is specialized function versus height-adjustable desks
Under-desk keyboard trays win when they can lower and center keyboard and mouse height without replacing the desk and that function removes a known recurring problem. height-adjustable desks win when they reach the same outcome with fewer dependencies, less maintenance, a more understandable failure mode, or a cleaner return path.
Normalize desk underside thickness and structure and track length and knee clearance
Compare both paths across the same desk, body position, computer, operating system, cable reach, workday, and shared-device routine, with every required dependency included. A complete under-desk keyboard trays package should not be compared with an incomplete alternative, and a retailer headline should not replace product-level compatibility evidence.
Use tray width for keyboard and mouse and height, tilt, swivel, and retraction range as tie-breakers
In a under-desk keyboard trays comparison, tray width for keyboard and mouse and height, tilt, swivel, and retraction range reveal the friction that appears after an attractive demo. Choose the path that can be installed, used, cleaned, updated, and recovered by the people who will actually own it. Prefer the simpler failure mode when performance is otherwise close.
Compare ownership, not only purchase price
Under-desk keyboard trays bring an ownership path of mounting holes, slide wear, wrist-rest replacement, lost knee space, and removing or repairing the desk later. Price that against the maintenance and replacement work of height-adjustable desks over one normal year. Include the value of time and the cost of losing the service while a proprietary part, account, or repair is unavailable.
Make the choice reversible
Use this test path before the return window closes: inspect the underside, mock up the final hand height, check knees through the full chair movement, then drill only with confirmed screw depth. Preserve the old setup and packaging until the product survives normal use. Choose the alternative immediately when the desk is glass or structurally unsuitable, the tray narrows mouse room, or lowering the entire desk provides a cleaner posture.