I think people are a bit outdated in their information. It's not necessarily true that the poly laptops are better deals now.
Also, almost all the Polytechnics I know have a Microsoft license, so students can bring their own devices to get Office, and probably all the relevant software.
For families with a tighter budgets, the IT show laptops are actually quite competitive. You can probably get decently spec'd laptops at under 1.3k from the IT show or external vendors. Just set it up, bring to school within the first week to the IT department to get the relevant software for the course, and off you go.
In the past with the vendors providing the software (Microsoft Office and Adobe Creative suite are the usual suspects), yes the value of the laptops in the Poly is high. Now, if you browse the relevant IT sites, you'll find it surprisingly not much cheaper. As for better support, all you get from the Poly at best is to drop your laptop there and they will send it for you and the wait times are very long. But if you send it yourself to the service centres, you'll actually get a quicker turnaround.
I've helped friends kids in the past 2 years try to procure laptops. We've found it to be generally false that the Poly is better value.
/Dan