A few years ago I bought from a Tom James sales rep:
2 shirts
1 RTW blazer
1 custom blazer
2 pairs of dress slacks.
The experience was generally positive. The sales lady was very pleasant. The prices are very, very expensive.
Regarding the shirts - -I would not buy them again, knowing what I now know about the better shirts out there on the market. They fit well of course, but the fabric/buttons aren't as nice for the price.
RTW blazer -- the "Innocenti Oro" line. I get lots of compliments on it, actually. The fabric is a nice tweed-like navy with faint lighter blue windowpane. The price was something like $450. Too much IMO for what I got.
Custom blazer -- this is beautiful and it fits me perfectly. The fabric I chose from a huge swatch book (she had a dozen or so swatch books, I recall). I picked out the lining and the various features of the coat. It was expensive though - - around $1,000. By the way, I probably wear that coat more than any other in my closet.
Slacks -- These were the fawnskin fabric. About $295/pair. Again, extremely expensive. Today, I think I'd rather buy Incotex or Oxxford for the same price (Oxxford would be on sale at that price). The fabric is so nice though, and the fit so perfect, that I actually went back about 2 years ago and bought two more pairs of the same slacks...
In sum, I think the more expensive TJ clothes can be high quality and you are essentially guaranteed a perfect fit. However, the prices are very high for everything -- both the "nothing special" mid-range shirts and blazers as well as the top of the line custom items.