I don't know what exact software you are talking about (PLC, HMI, Drive, Scada, Communications, OPC, etc...) but the concept of Totaly Integrated Automation is the key that makes Siemens software better than other software I have seen up to now.
Most of the softwares are connected to each other over and SQL database in your computer and when you make a project, after you archive it you have only one files that has it all = PLC + HMI + Drives + etc...
This is what I like about Siemens. The hardware we can argue about Siemens but the software concept is far better than other I have seen. Once I heard from a Siemens guy that software development part of the Siemens mostly the SIMATIC Manager is the most important part in automation.
On the other hand CX-One is a good software, you have a lot of hotkeys and visual side of it is not so bad, I only have problem with the commenting part and as mentioned the online debugging part is better than Siemens.