Maybe you've already made a decision, but here's my opinion:
The factory pahoehoe strings and the Aquila reds are different like apples and oranges.
Both styles are perfectly playable, sound good, and have strong supporters and detractors.
Personally, I prefer Aquila reds.
The factory strings are extremely elastic, and in my experience need to be tuned up from flatness every time you play. They stretch to half their original diameter and tend to not fill the nut slots.
The reds are less stretchy, more dense, and more stable in tuning.
To me, they represent an evolution in technology over the factory strings. They are also more expensive, so would represent greater "value" if that is a factor in your decision.
The knock on all Aquila strings is that to many folks, they feel "sticky" compared to the very slick and slippery feel of the factory strings. A light dusting of billiard talc powder solves that issue for me.
If you are buying a U-Bass without ever having touched one, it's difficult know which you would prefer, but trying different strings is part of the fun of owning one.