The Ham, I will try to answer your question.
When HS2 is built, it will not go beyond Birmingham in its first phase. Any benefits, were any to exist, would not be seen in Manchester, or anywhere else North of Birmingham for that matter. Manchester will be treated differently, as I see it, for being isolated from London Euston's newest railway line.
But let's not forget the important truth. It's already possible to get from Manchester to London in a couple of hours: by the time HS2 arrives, it'll provide a 10 minute reduction in journey time for £40bn: this impacts Manchester because a lot more good could be done by investing directly into Manchester *now* rather than waiting for HS2.
I believe Manchester should have P15/16 built *now* , which will be a positive impact , rather than waiting years for HS2 into Euston.
I'll also answer you in the context of business and the local economy. You can already get a fast, cheap, and direct train into London from Manchester, so HS2 doesn't improve the Manchester economy by a brass penny. You can already fly into at least two London airports from Manchester, quickly and efficiently, so HS2 doesn't provide a credible alternative for people, as options already exist, and exist without billions being spent on new infrastructure.
Manchester's Universities are already linked, by broadband internet, to institutions around the world. They are an important factor in the local economy. They don't need another railway into London, they need investment in technology and broadband.
Manchester could be worse off, I believe, if the brand new railway line into London directs investment into London because Manchester is not available via HS2. There could be the view that London has become even easier to get to, easier to invest in, because the new sexy fast HS2 line stops at Birmingham.
I believe Manchester will suffer if money continued to flow into London Euston, which is why the project needs to be scrapped. If it was about making the North the "place to be", the line would have been started at Piccadilly and gone south, instead it starts at Euston and , supposedly, works North.
I'm going to probably stay away from this forum for a while after this. I'm wholly against HS2, and will never ever use HS2, will never accept it. Some/most of you approve of it. This means that this discuss won't move on. I'll be against forever, you will be in support forever. We'll just go around in circles.
I will try to respond if I need to, but I'm aware that we could all end up repeating ourselves if we carry on. I just know that there will never be a time when I'll ever use HS2, and hope more people from the excluded, ignored regions join me in never accepting it.