A concern from consumers is that services will be restricted or rendered unusable by throttling selectively driving customers away from services.
A concern from Service Providers is that they will have to make deals with ISPs to ensure quality of service.
They're valid concerns on all sides and without Net Neutrality we've seen service restrictions, though they're advertised as benefits (e.g. free OTT messaging on flights from certain providers). We've also seen ISPs bully providers like Netflix into paying to deliver traffic their customers are paying to access (double dipping). It hasn't been the doom and gloom that was hyped but has definitely impacted services.
Under net neutrality I expect we'll see a degradation of cellular services or forced consent agreements as WISPs will not be allowed to downgrade or shape traffic otherwise.
It cuts both ways and I will be surprised if it makes much difference.