I am curious why you say icloud sync may be slow. I have it enabled and have used dropbox [ and have tested box]; bonjour sync, and local SSD for DTPO and DTTG sync. I use icloud for several other programs such as Keep It [not completely unlike DTPO in some ways], scanbot pro and scanner pro [totally different but still use iCloud ], photos, notability, and other programs that use one or more of these to sync… The omnigroup suite of apps syncs well and quickly, goodnotes, notability, the old Notebook, all move their data around reliably among computers and ios devices.
DTPO is the slowest and least reliable [in terms of not knowing when a file will show up on the non-original device]. I use both indexed groups and non-indexed groups in one database; indexed [all original files on a computer and indexed to DTPO] in a second database; and non-indexed [all original files resident in the DTPO database] on a third database. It doesn’t seem to make much if any difference in reliability of files being synced to other devices, especially ios devices.
DTTG in particular is nearly useless on iphone [7plus] and ipad pro as i can never be sure the files will sync from a computer to the ios devices in a few minutes. THIS IS NOT THE CASE WITH THE OTHER PROGRAMS, THE DATA FILES SHOW UP IN SECONDS OR MINUTES. Blaming icloud is a cop-out. Files [of any type I have tested, pdf, doc, access dbase, jpeg, raw, video …] placed in Dropbox, icloud based syncs with other software mentioned above, Keep It, or even icloud drive files show up in minutes on ios devices as well as other computers.
DTPO is the best software for my needs of storing and finding info in large databases, but the inconsistent syncing of files among the 3 computers and 2 ios devices I use is almost a deal breaker. I read the forum a lot and obviously numerous others have issues also. DTTG2 is better than the old way but is still flaky.
Given all the questions and issues that pop up on the forum your team has made progress, but still make too many excuses, and are still not there with a robust, user friendly syncing solution yet. You are a Mac developer, remember “it just works” is how it should be. Your software gets in the way of using the software.
For what its worth, I have been using Keep It on 3 computers and 2 ios devices in parallel with Devonthink/DTTG for 3 months with a large set of the exact same files [web, pdf, and docs mostly] in both apps, on the same computers and ios devices, and do not have the sync problems or delays with Keep it. Keep It works quickly and consistently to sync the files , tags, groups and metadata. It doesn’t do everything DTPO can but it does sync effortlessly so i can pull up data in a meeting with my ipad pro and the data is actually present on the ipad.