Solid choice for the price! The apartment could easily sleep six (one large bed, one small bed, and…read morea sofa in the bedroom plus a pull-out bed/couch in the living room), and for ~€100/night that's a good price. The bathroom was modern, and split with a toilet/sink in one room, and a huge tub (with shower head), standing shower, and two sinks in a separate room. The living area had a couch, chair, and a dining nook with a table and chairs to seat six or so. No kitchenette, but the restaurant downstairs was good and reasonably priced. The apartment also had a large balcony that would be great on a nice day. They have a couple parking spots in the back that are only for guests, but if those are full you will have to find street parking in the area (we didn't have any issues with the three cars in the group).
Overall a good choice in a pretty little Bavarian town. If you're looking for a place to stay for a ski trip to Brauneck, or for anything else that might bring you to Lenggries, Altwirt is a good choice.