Suspend vs RockShox Trailhead
Trailhead is the official RockShox setup app. Suspend works for the rest of your bike, too.
Trailhead is built by SRAM/RockShox to give riders factory-recommended starting points for RockShox forks, shocks, and seatposts. If you run RockShox top to bottom, it's a decent baseline tool with service manuals built in. But it's brand-locked, hands out factory numbers rather than rider-specific tuning, and is well-known in App Store reviews for asking you to sign in every time you open it.
Trailhead is the right starting point if you run RockShox and want the pressure that's already printed on the sticker. Suspend carries manufacturer-chart baselines for Fox, RockShox, Öhlins, Marzocchi, Manitou, and Cane Creek models, works with any other fork or shock from a weight-based starting point, and reads your ride feedback to recommend specific click changes, not just a baseline number.
Trailhead won't help if your fork or shock isn't RockShox. Suspend has chart baselines for six damper brands and still works on anything else from a weight-based starting point, so the app is useful on whatever bike you're standing next to.
Riders in Trailhead reviews complain that the app "gives the pressure that's already printed on the shock." Suspend listens to how the bike felt on the trail and tells you what to change, click by click.
"It's a decent app but the fact I have to log in every time I use it almost makes me not want to use it," wrote one App Store reviewer about Trailhead. Suspend stays signed in.