Golden Fleece Made by Martin Greenfield, the Golden Fleece is Brooks Brothers's highest quality MTM suit and starts at $1,250 for Super 100 fabrics (book A), $1,250 for Super 120s (book B), $1,650 for Super 130s (book E) and can go as high as $2,850 (Super 160s Loro Piana fabric).
The brochure I received says the Golden Fleece suits have "full canvas camel hair chest pieces, linen under collars, genuine horn buttons, hand sewn buttonholes, and over 18 hours of workmanship". Turnaround is about 8 weeks.
Makers The Makers line, from what I gathered, uses a half-canvassed front and hence cheaper and quicker to make (5 week turnaround). Smaller selection of fabrics as well. Not sure what the pricing is but obviously lower than Golden Fleece.
Select I didn't inquire into the specifics of the Select line but assume that there is even less handtailoring and lower quality construction (and an even lower price point). The brochure says choose from "100 fabrics and specify your size, model and options with a turnaround time of only 4 weeks."