My most recent experience playing live, with 4 players (at least one of which was new to Viticulture, but experienced with other worker placements) took about 2.5-3 hours. The computer handling the interface might speed it up slightly, but probably not significantly (except for the year-end maintenance of aging grapes/wine, which can be tricky).
I do not play games live on BGA, so cannot advise on what it is.
I could throw out the answer of "25 minutes or so" and let Cunningham's Law take effect...
One bit of advice -- don't trust how far people are to 20 points to determine how far the game has progressed. Early years provide very few points compared to later years. 10 points is about 2/3 of the way through the game, 15 points is nearing completion. At least in my experience.