I use Visbiome - I take an extra-strength packet (900 billion CFU) twice a day. As others have said, both Visbiome and VSL #3 (they are quite similar) are expensive if used in meaningful doses. The extra-strength Visbiome does require a prescription, but the lower strengths do not. My pharmacy searched a bunch of discount programs and got the cost of 60 extra-strength packets (a one-month supply for me) down to around $270.
The main purpose of bacterial probiotics for J-pouchers is the prevention of pouchitis, and possibly some help with managing it.