I use International Suit which is off of Soi 2 and Sukhumvit. In the Ploenchit center on the corner across from the Marriott. I went all over bangkok for a couple days and decided on them. Been back 3 times and the guys are actually Chinese. Mr. Tommy and Mr. Surat the son. I'm very happy with them. I'm sure most tailors are good but once you find one that works for you why change?
I don't care how many pictures the owners have with Steven Seagal I have found my tailor.)