I tried it today and liked it. They use fried tofu triangles, and they do have a touch of flavor – possible the tofu is marinated in something before frying. I asked for “spicy” and got a satisfying quantity of thinly sliced jalapenos. Along with the cucumber, carrots, cilantro and onion, it was a very satisfying sandwich.
Making a comparison with Clear Flour is difficult. Mei Sum uses a nice, traditional, lightly-crusty roll for its sandwich with a soft interior. Clear Flour uses their sesame baguette, which is crustier but not too crusty for their sandwich. Clear Flour also smears their bread with a sambal mayo – far from traditional, but every bite of their sandwich is tasty. The Mei Sum version, the bread not being smeared with pate or any substitute, gives you some bites that are a bit lackluster compared to others.
On a side note, the pork pie at Mei Sum was on par with the ones at May’s Cake House in crisp flakiness and the woman who made my sandwich was warm and friendly and asked me questions about myself. A contrast with the no-nonsense attitude one encounters at many other Chinatown places.