Do not make the choice on the option of 5 or 6 gears. Look into the ratios you need.

With that said there are many ratio choices for the T56. I have a close ratio and find 5th to be pretty much useless. I love the close ratio 1 to 4 and would not be dissappointed if 5 was super tall for cruising and there was no 5th but it's there and it's okay.

Like Goldduster said, nothing shifts like it. If that is important to you, T56 Magnum is your only option.