Now the truth(?) comes out. IF that's what you want, why didn't you ask it that way?
Perhaps because someone would have answered with something like "Which is better: Ford, Chevy, or Toyota?"
The truth is that they are all fine. They will all do the job you're asking them to do. The differences actually end up being PREFERENCE and SUPPORT (Which can you get the best personal support for locally?)
Or with something like "What do you already use?" It doesn't make a lot of sense to bring a single "off-brand" PLC into your plant. Though it may be "better", it is still "weird" -- unfamiliar software, uncommon spare parts, and longer learning curve - which all lead to longer project times and longer downtime.
And when you asked to compare the S7 -- there are so many different versions of the S7 that it is again nearly impossible to compare. Pick one! Or better yet, pick a particular project with defined requirements.