Like Andrew, there is more than one jack plane in my shop.
If you count the low angle jack, there are five #5 size planes in my shop. There are also two #5-1/4 size and one #5-1/2 size. One each of the #5s and #5-1/4s are set up with heavily cambered blades for use as scrub planes. The #5-1/2 came with a cambered blade which has been replaced with a straight ground blade.
They all come in handy for different needs.
A corrugated sole is preferred by some, doesn't make much difference.
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)