Hi packrat, I haven't used a lot of Cat 6 cable in the last couple of years, but yeah, as far as I am aware, the colours are the same. I can't imagine why they would go and change the wire colours at all, in fact, if they did, some of the installers I know over here, would end up running home, crying, due to not knowing how to deal with such a move.
One thing that the Cat 6 cable here has that Cat 5e doesn't, is a "X" shaped seperator between the twisted pairs, inside the cable sheath.
I've used a few inches of voice grade ribbon cable to connect a router to a switch, running 100baseT successfully. However, if I tried 100 meters of that cable, it would surely not work. The cat6 certification means that I will get 1gb thru 100 meters of that cable, guaranteed. Cat5e might work, but not guaranteed. But I wouldn't want to bet on it, and an installer wouldn't either. Shorter lengths are more likely to work, but he'd still use the certified cable for everything.
You certainly want to use the right cable if the customer is paying for it. It is really as important that you terminate the cable properly as it is that you use the right cable. Sloppy terminations can make CAT 6 cable return Cat 3 performance.
I just spent 3 days at a manufacturing facility that was having trouble with their shop-floor data entry stations. They were having problems, it seems - and it was my job to prove whether the cables were the issue, or if there were issues with their software.
What did I find? Well ...
The first problem is that I got the job. OK, so the manufacturer likes my employer. I get that. My employer has a long relationship with this firm, etc. What kills me is that no one in the shop has any special Data knowledge, and our tracing / testing gear is pretty primitive.
Even more surprising was that a data-specialty contractor was working another project on-site while I was there.
I've never had formal LV training - let alone BICSI certification. Still, it was clear to my untutored eye that the Cat-5E and Cat-6 cables were installed by someone whose main qualification seems to have been draping tinsel on Christmas trees.
Excessively long runs (500+ ft.) and multiple splices seemed to be the rule. Wires frequently lay atop magnetic ballasts and hot pipes. Support was generally lacking, or rigged from ceiling tie wires.
I see this sort of thing far too often. Personally, I consider it unethical to run "Cat 6" unless you know WTH that means- and follow the rules. This includes clear cable identification and some form of performance testing.
Shame also on the customers who specify "Cat 6" when they'll never need anything like the performance of Cat-6. They're setting the stage for some substandard kludge- sort of like specifying a BMW, and not noticing when the salesman substitutes a plain old Chevy.