Hey Neil,
I used to use Bridgestone 6 because it was supposed to be straighter. It wasn't that straight. My swing improved and I found out the NEXT Tour S was a good ball for me. Good trajectory and boy it goes down the fairway. I like the feel of it and also around the greens. Checks up nicely and it feels good putting. Somehow my putting improved also. Maybe my iron shots are closer? But it is what I like.

Definitely the NXT Tour! Great off the tee and absolutely great around the greens !

Can't go wrong with an NXT Tour ball, I have a high swing speed as well but I play the new Pro V1x. I know that $50 a dozen isn't something most people want to pay for golf balls for just going out and playing to have fun with your buddies. I think the NXT Tour would be a good ball for you, although I think the softer NXT Tour S is the only one that comes in yellow in the NXT family. The new DT Trusoft's come in yellow also, but in my opinion if your wanting to stay similar to the E6 ball. Definitely the NXT Tour.

If price isn't an issue, I would try the ProV1 or the X. If it is, the NXT Tour is a great ball as well. I usually play a ProV1, but I just shot my second lowest round of the year with an NXT Tour on Sunday. To me, the difference is subtle enough, that I don't notice it. They're both great!

Get fit!