SyncBackPro and SyncBackSE can access the files and folders on any device that SyncBack Touch is installed on. SyncBack Touch can be installed on Windows, Linux, macOS and Android devices. This means, for example, you can backup all your pictures on your Android device by installing Touch on it and then using SyncBackPro or SyncBackSE to backup those pictures. For additional details, refer to SyncBack Touch guide.
The SyncBack Management Service (SBMS) provides a way to monitor and manage remote SyncBackPro installations. For example, you may have SyncBackPro installed on all the computers in a department. With SBMS you can check to make sure profiles are being run on all those computers, control what users can do with SyncBackPro on those computers and also manage the profiles on those computers.
With SBMS you have the SBMS Windows service that you install on a Windows computer, preferably a Windows Server computer. You also have the console program which you (as the administrator) use to access and configure SBMS. The console program can be run from any computer. Each installation of SyncBackPro communicates with SBMS in the background, e.g. it tells SBMS when a profile has been run. For more details, refer to SBMS guide
Which should I use?
It depends on what your requirements are. For example, let's say you have SyncBackPro installed on multiple remote computers. They may all be in different cities or countries. Your job is to make sure the backups are running on those computers. In this case it would be best to use SBMS as you can monitor the backups without needing to visit each computer.
Another example may be that you have a department of computers that all backup to a file server. In this case it may be best to use SyncBack Touch. You could install Touch on each computer and then SyncBackPro on the file server (or any Windows computer). Then you create a profile to backup each computer that SyncBack Touch is installed on.
It is possible to use SyncBack Touch and SBMS at the same time. For example, you may want remote SyncBackPro installations to backup to SyncBack Touch running on your Windows file server. This can be done over LAN, WAN or the Internet. You could also have the SyncBack Management Service running on the same server as SyncBack Touch (or any other computer the remote SyncBackPro installations can reach via a network). SBMS can then be used to monitor those remote SyncBackPro installations.
If you use SBMS then you need a license for each SyncBackPro installation and also a license for the number of simultaneous connections (computers) to SBMS. Unlike SyncBack Touch, you cannot use SyncBackSE with SBMS. Only SyncBackPro can be used with SBMS.
If you use SyncBack Touch then you need a license for each SyncBack Touch installation and a license for SyncBackPro. You get free 2 SyncBack Touch licenses with SyncBackPro and SE. SyncBack Touch can also be used with SyncBackSE and SyncBackPro, although only SyncBackPro has the ability to use multiple SyncBack Touch devices in a single profile.