Ting,
Q Series is at end of life from a production point of view.
Spare parts will become harder to get, and more expensive, in the very near future, and this process
has already started.
The IQR is priced very well, sometimes even cheaper than the Q on certain modules from my experience.
The IQR platform has been widely adopted, I use it myself for our project work.
We have moved away from Q Series all together.
Not knowing your applications, it is hard to comment on CPU selection.
As with any equipment of this nature, customers and their needs, drive development of any product, true the Q series is a
very capable PLC, the IQR is the next evolution of a stable platform.
Many customers are future proofing their plant in the form of PLC selection and upgrades.
The availability of spare parts is a driving factor, more so than functionality.
Hope this assists
Regards
Colandra