Allen-Bradley or Siemens?
This is probably the first argument every new controls person walks into.
Someone swears Allen-Bradley is the only thing worth learning. Someone else says Siemens is the future and Rockwell is overpriced and stuck in the past. Both of them are usually talking about the one plant they know best.
The honest answer is less exciting, and more useful: in Canada, you'll see a lot of both, and the right one to learn first is the one used by the kinds of plants you actually want to work in.
Where you'll run into each one
Walk into a lot of food and beverage plants, packaging lines, automotive suppliers, and mid-sized manufacturers across Ontario and the Prairies, and Rockwell / Allen-Bradley gear is everywhere. ControlLogix and CompactLogix controllers, PanelView screens, PowerFlex drives. Part of it is history, part of it is support — the local distributor knows the parts, the maintenance shelf already has spares, and the electrician on nights already knows the software. Plants don't rip that out because a forum said another platform is more elegant.
Siemens shows up a lot too, especially in larger, more integrated operations, some process plants, and companies with European parent companies or European-built machinery. If the line came over on a boat with the OEM's name on it, there's a decent chance there's a Siemens controller inside it, running in TIA Portal. You'll also see Siemens SCADA and drives bundled into those bigger systems in a way that feels more all-in-one than the Rockwell world tends to.
Then there's everything else, because Canada is big and plants are stubborn. Omron in some packaging and automotive work. Schneider in some process and municipal work. Mitsubishi here and there. Ignition sitting on top of all of it for SCADA in more and more places. Anyone who tells you there are only two platforms hasn't spent much time opening other people's cabinets.
The software feels different, the job doesn't
Studio 5000 and TIA Portal don't work the same way, and switching does involve some swearing at menus you can't find. Tag-based versus more structured data handling, different ways of organising code, different habits around function blocks — it's real, and it does slow you down for the first few weeks.
But underneath that, the work is the same work. Inputs lie. Outputs fail. A sequence gets stuck on step three because a limit switch hasn't made in two years and nobody wrote it down. If you understand sequences, interlocks, alarming, and how to prove a sensor is actually telling the truth, that understanding moves with you. Employers who hire experienced people know this. That's why plenty of postings say Allen-Bradley or Siemens experience, not both, perfect, no exceptions.
Where postings do get specific — and they often do — it's usually because the plant can't train you from zero on their system while the line is down. Read that part carefully. "Experience with Siemens TIA Portal" in a posting for a plant that runs Siemens is not snobbery. It's a crew that needs help now.
So which one first? Use the postings, not the arguments
Do this before you spend money on training: pull up the live jobs in the province and industry you want, and count. Not opinions, actual postings. Which platform is named most often in the roles you'd apply for in six months? Learn that one first.
If you're in general manufacturing in southern Ontario, that count will often lean Rockwell. If you're aiming at a specific large plant or an OEM / integrator that builds European equipment, it may lean Siemens just as clearly. Both answers are correct, for different people standing in different places.
And once you've picked, stay with it longer than feels fun. The goal isn't to have touched a platform. It's to be the person who can be handed a fault on it at 11 p.m. and work through it calmly. That takes repetitions on one system, not a tour of four.
What not to do
Don't list both platforms on your resume as if you're fluent in both when you've done a weekend course in one of them. Controls is a small world in Canada. People move between plants, integrators talk, and the person interviewing you may have commissioned the exact line you're bluffing about.
Don't refuse work just because it's the other platform, either. Some of the best learning happens when you're slightly out of your depth with a senior person nearby who knows that system well. Just be upfront about where you stand.
Pick one, get good, add the other when a real job asks you to. That's not a compromise. That's how most people in this trade actually built their careers.