Exactly Lu! There just is not enough data out there. VSL#3 has become the recommended one, because it actually has some studies done with pouchitis and IBD, whereas most others have not. And, even VSL#3 is not 100% effective for everyone. Some people cannot even tolerate it.
What I did was look on PubMed for studies on probiotics in regard to IBD, didn't matter to me if it was UC or Crohn's. There wasn't much out there and what was there, was either small studies or not very conclusive. The problem is that with probiotics being unregulated supplements, there is no consistency. You can have the exact same lactobacillus in a hundred different products, but they really are not the same, because they are different strains. One strain may die in the stomach while the other does not. The one that lives still may not have what is needed to stick to the bowel wall when it gets there.
So, you really cannot just buy whatever is on the shelf and think it will work because it has X-Y-Z probiotics. But there is no harm in it either (other than to your wallet). It is hard to prove a negative. "I didn't get sick, so it must be good." Could just be coincidence, especially when you are dealing with IBD, which is very random with spontaneous relapse and remission.
So, if your doctor has a brand that he recommends, it is worth trying, because he probably read something about it. Otherwise, just pick one and try it and see.
Jan