Max base is level 30, in pwi faction bases provide free stuff like buffs/blessings/shards/arrows etc. the same thing applies in epic, unlike other servers, here there is a reason why we do base quests, Archers have the base arrows which are better than the ones in gods giving because of the +150/200/250 attack they give. Base blessings like divine strength can be obtained multiple times if the base has lv 5/6 armory...(red hall) which gives +5 attack and def and the blessing can also be socketed so you can put shards in it so like extra 45-60 vit depending on which shards. base buffs for soloers that don't have eps or other stuff, not many people use those buffs because of the bh pots dropped by puppeteer. The other stuff is mainly for pwi but arrows/blessings are what people mainly do base quests for, that and helping out the faction.
This^^ and Gwyn ^^ So glad to see others know why it is extremely beneficial to level a faction base. I do miss the old pwi days of Trials though