You asked about the worth of speed and the answer is:
Speed is very important if you are constantly looking for the edge. If you are a LEVEL trader, meaning you pick your spots and place your orders, a less costly web-based solution like J-Trader or FFastNet is sufficient. In most cases though, the transaction cost is higher for the lower cost systems.
If you are looking at cash prices or news as an indicator, you want to be first. This necessitates a system that is quick and reliable. You have to decide if it is worth it for an upgrade. But be aware of the different transaction costs that are associated with different platforms. ie. FFastTrade offers: Remote Pro: $550 with a $3.32 Round Trip rate and their Web-based solution is: $175 with a $4.32 Round trip including exchange fees.
At 750 lots per month the two systems become equal in cost. So if you trade that kind of volume you would want to upgrade anyway.
TT is offered through several FCMs and IBs and the transaction rate is the important factor. They have a great system and longer term record than most of the other systems.
I work at FFastTrade and I would give the edge to TT on stability due to the fact that they are still mainly connected to the Fix 2.3 API. The CME announced last week that this API is now second in speed, but I can tell you form experience it is currently more stable. As far as speed goes, FFastTrade may be faster due to the architecture. Explaining the architecture is another issue, but I can tell you that trades are turned around in less than .50 of a second.
In any case, the CME is currently having issues that are very dangerous. I would recommend caution to anyone trading the e-minis right now. I am recommending extreme caution to all of my traders.