Like many other things, the whole streptococcus in probiotics issue is one for which there are multiple -- and sometimes contrary -- opinions. If you search here on the forum for "probiotics" threads, you'll see that some doctors have advised staying away from all strep strains, and others have argued that those strains, in those formats, have no negative impact.
If you've been sensitive in the past, might it not be good to start out with a single strain probiotic, and then add another single-strain and so on, so that you can monitor what, if anything, seems to be problematic rather than helpful? I agree that a good-quality multi-strain probiotic is ideal, but it might be tough to discern the wheat from the chaff in your case. Many folks here have used Klaire products, and we like the Renew Life line.
I would search this forum for the probiotics threads, however; there's a lot of information there, including research papers, personal experiences dating back some time among the participants here, etc.
Good luck!