Like all the 'nationals' one hears 'stories' about them, but I hardly ever come across them.
That is exactly why I said this:
I'm not making any further comment, except to wish you luck.
I think that unless you've actually worked for a company, it's very difficult to give an opinion about working for them unless you base it on the kind of rumours that abound in a small industry like ours.
The trouble with any biggish company is that they are only as good as their worst technician, and speaking from experience, the worst can be terrible.
Whatever happens, the fact that someone is being given a 'legup' from a big company has got to be a good thing. If the OP is lucky, he will learn lots of things about doing pest control well. If he's unlucky, he may see how not to do it, or he could get a mixture of the two. One thing is certain, he will get experience, and that has got to be good.