GNER were without any doubt the best TOC and offered the best service of any TOC.
GNER phoned me to tell me they'd found some property I'd lost on a train then denied all knowledge of it when I turned up to collect it. I've still no idea where it went.
One GNER member of staff shouted "What do you want?" at me when I entered the ticket office.
Another GNER member of staff refused to serve me as I was queueing in the wrong place, despite the fact I was the only person in the queue (apart from the person he was serving at the time) and there were no signs telling me where I should have been queueing.
From my experience, GNER offered the worst service of any TOC. However, given that I've never travelled on any of the other ECML franchises my vote has to be for Cross Country....