This kind of question really begs to be qualified. Further information that is crucial to making sense of this question are:
1. What are YOUR drivers as a customer for buying a PLC?
2. What is the size and nature of your organisation.?
3. What type of control applications do you undertake, how large are they?
4. What is the skill level of the people who will be working with your automations system?
5. What is your automation technology history, and do you have a plan for your future?
Then the answers you get should be carefully judged according to who is giving them to you:
1. What are the DRIVERS behind this person’s anwer?
2. What is their experience in your kind of industry and type of organisation?
3. Have they ever done the kind of control work you do?
4. What is their real skill level?
5. What is their technology history?
If you seriously consider all these things then it is obvious that asking this question is tantamount to asking, “what is your favourite car/SUV/wheels?”. All your answers will fall into one of three categories:
1. All modern cars will get you from A to B.
2. What kind of person are you and what sort of driving do you do?
3. Or “FORDS RULE!!!”, (substitute your brand loyalty of the day). Sweeping generalisations characterise these guys. References are made to brands WITHOUT being specific to any exact products or any useful informations that might validate their claim.
This is why this kind of thread is called a pi$$ing contest. The question is too vague to have meaning, you have no way of verifying the qualifications of those who do post replies, and the basis on which they do so is shifting sand.
In the meantime the world go to he11 in a handbasket; some 50,000 odd humans needlessly die everyday of poverty, disease and neglect, and we will whack on about which PLC we think is best…sighs. Oh well at least Easter is a day or two off work.