To be honest I'm kinda of the opposite opinion to Scott. The body goes through a lot before it gets a pouch. If you can give it a bit of extra support why not.
It is true that the jury is out on the benefits of probiotics. That's because stomach acid is mega strong stuff, so most probiotics don't even reach the gut. The 2 that have been proven are VSL (freeze dried) and symprove (liquid).
Now just because they get to the gut doesn't mean they are beneficial, my surgeon says they are a complete waste of money, but my specialist says they are probably a good idea.
After a traumatic event (like losing your colon), months of bad diet, then a new gut being created, I can understand why giving the body a bit of support with the bacteria is a good idea. Especially as the diet you will be eating at the time is mainly the stuff that promotes bad bacteria (sugar and yeast foods)
Personally I did... Did it make a difference? I believe so! I can't prove it though. We could probably do a survey on here of people that took probiotics early doors and how many of them got pouchitis!
People who have had pouchitis do state that probiotics help keep recurrent flares away, so makes sense to me they would help prevent flares too.
Your body, your choice I guess. Some people on here use align which I believe is much cheaper, again I can't personally vouch for its effectiveness.