Tom James suits can be a great timesaver and a good way to get great fitting custom clothing done quickly. However, its important to know what you are getting with them.
The basic principle behind their offerings is that they come to you with the clothing. They do the measurements and based on that, make the suits, sportcoast, shirts, or whatever you need done. Its a good idea in theory, especially if you're a guy who makes good money but just doesn't have time to get out shopping. They market themselves as offering the world's best custom suits.
Understand though that you will be paying a good premium to get this convenience. Plus, you will need to deal with a salesperson in your office or business. They will definitely push you to order, probably more than you need.
You can order many levels of quality on their suits. Its rumored that the top end designs are done by Oxxford, as they are part of the same company. Do some research before you purchase. Most reports of the mid-level Tom James lines are fairly good. But again, you will be paying a premium. As of today they offer English, Classic, Italian, and the Prestige cut, which has English cloth. Each of those styles has several coat and pants styles underneath that. So you definitely will have a lot of options.
I would use extreme caution when buying used or returned versions of their suits. Remember that these are custom measured and tailored suits, so the standard measurements won't quite apply to you. It may be very expensive to get new alterations done.