Hayward has the better (consumer friendly) SWG concept - power supply and control electronics are separate from the cell making the cell replacement much cheaper. Pentair SWG cells have most of the electronics integrated into the cell body making replacement costs twice the price of a comparable Hayward.
Raypak is the "best-of-breed" heaters, neither Pentair nor Hayward come close.
Pentair has the better control system. Way too many complaints here about Jandy AquaLink and whatever Hayward calls theirs (OmniLogic? GoldLine? more options than socks in my sock drawer...). Aside from some non-obvious programming logic, Pentair is very easy to figure out. All the others seem to want the end user to use their cloud-services for extra features as opposed to Pentair which is all self-contained, no need to link up to the internet.
Pentair has the best-of-breed variable speed pump, there's nothing better than the IntelliFlo on the market. I also personally think the Pentair Clean & Clear or QuadDE filters are the best. I love my QuadDE and, if you don't mind DE filters in general, it is much better than the standard grid-based DE filters.
So, at the end of the day, they all have some good and some bad qualities....I think you'll want to stick with a system that the PB knows how to install. If you're asking a Hayward-only PB to do a Pentair installation for you, that's asking for trouble in my book because they will be entirely unfamiliar with the systems, how to hook them up and who to call when they get neck-deep in trouble with no way out....
That's what is really helpful. It's nice for people to give their opinions but also giving the reason for their preference helps when someone's trying to make a decision.