This is an absolutely charming bed and bar (vs bed and breakfast). The music doesn't last past midnight, so if you're out exploring Zürich into the evening it's unlikely to keep you awake. The matron is warm and welcoming and has plenty of recommendations. Aelpli-Bar is well situated in a great part of town for exploring on foot, and an easy walk or bus ride from the train station. The accommodations are simple, bit if you're used to semi-private hostels this will be familiar and quite comfortable. If I have occasion to return to Zürich I'll look first for a room here once again.
Note: the front door opens automatically when you approach close enough. Don't waste time looking for a handle.