Yes, that's exactly what it is, a filler.

Professionals don't want to fill, they want to correct the actual defect. AG stuff really isn't in the same league as the products first mentioned.

They are OK for everyday but after saying that the Meguiars stuff wipes the floor with them for that too.

It takes a while to get your car to a decent level paint finish wise but once it's there it becomes quite easy to maintain. In other words you wont have to use SRP every other week.

Have a go with Meguiars Ultimate compound instead of SRP, you'll see the difference