I am looking for a binder, but I don't know which type of binder to choose.  I am not sure whether to look at T-Kingdom or Underworks.
Which ones have worked best for guys? There are so many it is difficult to choose. 

I have heard mostly negative reviews on binders from T-Kingdom, so I wouldn't go with that. I have a binder from LoveBoat (http://www.lesloveboat.com/shop/index.php?language=en) which is a company based in Taiwan (I think). Underworks is the most commonly used company and is better for people with larger chests. LB has some binders for larger chests as well, but is mostly good for people on the smaller side. Another thing is they have such a large selection that it is sometimes hard to know what you're going to get as far as binding ability. I've ordered three binders from there, the first two were great but the third one I got just didn't work at all. So it's kind of hit and miss.

From Underworks the two binders that seem to do the best job for people are the tri-top 983 and the double-front 997 (http://ftm.underworks.com/)

But yeah, it helps more to answer your question if we know what size your chest is.

I LOVED the Ultimate Chest Binder Suit style 967. It bound just as well as the double front/ tri top and didn't ride up It was comfy and not excessively hot. I was very small chested, maybe tanner stage 3, so IDK how well it would work for large people. But I recommend it 100%. It also has shorts sewn in, so you can have a manly shaped rear end or something. In the shorts is a packer pouch and split crotch for bathroom ease. I personally cut the bottom completely off so I could use my STP more easily, also the pouch isn't STP compatible unless you modify it. But I think the pros definitely outweigh the cons!