Hi,
I did the one-month GTC course in March 09 after looking at TCA, Amplify etc. and a couple of courses in the US. I previously worked on trading floors for 1st tier IBs in London and NY for the last 8 years, so had the original training under my belt already but didn't work as a flow trader/daytrader. At GTC, My fellow group was pretty high calibre, some of them ex-Invetment Bankers looking to switch into trading (with more than 5+ years in Fixed Income), some recent graduates from the French higher universities which wanted practical experience for their resume (also classic IB job candidates), and the rest were looking to make job switches into trading from various backgrounds. Everyone was on-site in London.
The reason I chose the GTC course over other offers was that I wanted a course that was more serious than the "let's trade from home" garden variety, which too often only trains you in specific markets using their own software, rather than industry-standard TT software etc, and does not prepare you to survive as a professional prop trader later on. It was worth paying the course fees as a result.
For me, the selling points were:
(a) I was on-site on a trading floor, with mature senior traders around for information/observation/questions
(b) the course had a practical focus and a solid structure, i.e. daily practical exercises, which built up trading skills sequentially while simulation-trading live in ALL major FI derivs markets (Eurex etc)
(c) I ended up with a thorough feeling/understanding for the pace of these markets (2yr/Bobl/Bund, Euribor/Libor, Eurodollar etc) and could decide which were the markets best suited to my trading style
(d) the course started with basic trading strategies but built up to the complex synthetic strategies, while requiring you to do mental math by calculating several moving variables in your head (you can always build your own spreadsheets later to simplify the exercise)
(e) GTC has only recently legally separated from FTC/CFT, due to its training focus, but has close links into the major EUREX clearing/prop houses. They have an established feeder structure into CFT, Sigma Derivs and other high-caliber prop trading houses that are clearers on the Eurex exchange, which was important to me in case I wanted to make this transition.
A note on trading software - they use TT (the general industry standard) plus a 3-D software that makes it easy for you in the beginning to follow the volumes etc in the markets. You actually can see the order books and sharpen your technique / execution skills during simulation trading, which other competitors do not provide to the same standard.
The things that were less important for me (and which may be a weakness, depending on what your focus is) was that if you are looking for a thorough introduction/review to trading theory, you will have to do this in your own time at home (they do provide additional materials if you ask though). A second point was that you have to be self-motivated. Lectures introducing new material etc were usually held around 9/10am, but you are encouraged to trade from market open at 7am until market close, however it is up to you if you take this course as a "job simulation" or just want to get the training.
Hope this helps. I was happy with the 1-month pro-trader version of the course. The second month is designed to give you simulation practice, choosing your markets and strategies and refining execution and technique so you make less mistakes and are confident when you go live. At the end, in month 3, you trade live money.
Hope this gives you an idea and a basis for comparison to other courses.