Mod is very much playable and richer with features and more complete than most mods, with base 0.27.1 version of the game, patched to 0.27.2. Make sure to download WSE from the Silverstag Nexus page, because that is the WSE 3.2.0 version which you need to run Silverstag, later versions of WSE doesn't work with the mod. Put WSE 3.2.0 in the Modules folder and run WSELoader.exe in order to get the Warband client running, select Silverstag and you're good to go.
The only major issues in my opinion is some imbalance in troop trees (which I've made some edits for myself to fix most of the most glaring issues), aswell as impractical weapons and some red error text that can appear moderatly often in tournaments and clog up your whole screen, and rarely in field battles/sieges.
It is unfortunate that the development was abandoned because this is in my opinion the best mod for Warband, but it is also understandable due to Taleworlds complete incompetence when it comes to communicating with its community, by the time the mod project was abandoned, people didn't know whether Bannerlord would be released in one month, in one year or not until another five years. Zero communication during the development of a sequel leads to the modding scene of the current game to grind to a halt. Why is this not the case with Skyrim? Because Bethesda properly communicates with their community that the next installment in the Elder Scrolls series won't be out for many more years, atleast 2-3 more.