"Tier 1" is pretty much such a loaded/marketing term that it's about useless for any sort of technical evaluation.
The generally accepted meaning for "Tier 1" is a provider that does not pay for transit. This really doesn't have any direct correlation to the quality of service they provide, or how much bandwidth they might be willing to offer you. (And, in fact, peering with a single "Tier 1" provider exclusively for all connectivity can be dangerous, c.f. all of the various depeering disputes that Cogent likes to have with TeliaSonera, Level3, etc.)
That being said, all of the universities I have had interactions with did not get their bandwidth exclusively from anyone meeting the above definition of "Tier 1". (Edit: There might well be univerisities that do fall under that category, but certainly not all of them, and buying from a "Tier 1" provider or not is not a particularly meaningful way to characterise the quality of their network connectivity.)