Sandwich shops seem like Mexican food here; always hit and miss. 1Bite to Go looked like it had potential but the time I visited the Rueben was drenched in Thousand Island and the bread was soggy. I’ve looked around and haven’t found any other shops that are really specializing in sandwiches, besides Vietnamese Bahn Mi.
Woo Taipei in Zhongxiao Dunhua. Nom Nom near Shida.
The po boys at NOLA.
Toasteria; the new Dongmen one is very nice but make sure to get reservations. You could also try the cheesesteak sandwich down the street at Focus Kitchen. Nearby, Panos is OK, but not great.
These types of places are hitting on rough times, though. Mactugal, Cozi Burger, and Eating Time all closed not too long ago.
Speaking of Viet food, I’ve yet to find really good Viet sandwiches (or food) in Taipei. There are some OK ones about, like at Gongguan night market, and near Houshanpi MRT station. Coming from Texas though, the Viet food here is pretty mediocre.
I would hesitate to call this place the “best,” but I’ve recently discovered that the sandwiches at Mt Kao (in an alley near Technology Building MRT Station) are pretty fine, especially if you’re in that part of Taipei. Included as part of their sets, the house-made salad dressing will make you sit up and notice that these guys are serious. The folks running this place are really nice too, if that matters to you. Be aware, though, that they’re closed on Mondays.
This is a hard one. If you asked the best Korean food, burger, taco or something like that I can give you a place I think is the best. I guess sandwiches are just not very high on the list of foods I want to eat in taipei with all the options here. I really can’t say when the last time I ate a sandwich in taipei.