Since I first going involved in running a mc server the biggest problem I've had to deal with is losing half my players each time mc vanilla updates until I can get my server up to current. It forces me to update b4 plugins are ready and even b4 spigot is stable. Recently a bug in 1.9.4 slowed my server to the point I was losing players. viaverion allowed me to run 1.9.2 with no loss of players. It also allowed me to run my 1.9 mods again. More importantly it has let me wait till everything is stable b4 updating. I no longer worry about hurriedly getting things ready for an update. I can rest easy on a stable version knowing everyone can connect. I see already that I don't have to worry about 1.10 and whatever bugs it will bring because compatibility is already being worked on. I personally believe viaversion is the best thing to ever happen to Minecraft.