I do have the original in my 97, and it is always on a trickle charger. My 97 I have kept completly stock, and although I would buy a Ford battery to keep it stock, it wouild be nice just to have the eyeball for that "stock" look.
My 99 is my truck that I keep play with, although it does have a replacement Ford battery w/o the eyeball) I believe the Ford batteries are made by Johnson Controls.
On another note....As far as the optima batteries...Here at work, we have battery banks to keep this facility up before the generator kicks in. They are 1400AH 6V batteries (qty of about 300). They are gel cells. Comparing my facility to other facilities that use lead acid, the lead acids will outperform gels any day of the week by quite a bit. What may be an advantage is with offroad conditions related to vibration.