No experience with Sage.
20+ Yrs Exp speaking:
Mfg Pro:As good and stable as most. Minor issues.
Foresight MXP:As good and stable as most. Minor issues.
Syteline:Fair, suitable. Issues. Converting to MS-Sequel soon.
(difficulty finding qualified Syteline Programmers).
Recommend: Go Unix db server, App Server, WinNt Terminal Servers architecture.
Will design, install, implement, consult for fee.