I think Line 6 have very fairly gained a reputation for over-marketing their stuff of recent years which doesn't quite deliver so some scepticism is definetely warranted I agree. Conversely I think that they don't get the attention they deserve when they make an excellent product like the DT.
Was researching this yesterday but the YouTube reviews haven't really highlighted anything other than the amp modelling yet. At 1 grand the majority of the purchase price seems to have been sunk into the unit being used as a main controller.
From a signal processing standpoint it doesn't appear to offer anything better than the reverb/chorus/delay you could get from a cheapo unit. My feeling is that someone would be better off with a valve amp + effects unit for the same price (or less) than buying the Helix.
I suppose your definition of what modelling is there and whether it's good or bad depends on the environment and application of a sound or tone. As always subjectivity is there when listening to tones and music. I do find lee and chappers' reactions interesting on this video as I do value their opinions and find them to be generally pretty honest in their response on gear.
I've been wanting a pro effects unit for ages now, the modelling is better than the unit I have at home and living in flats I run direct into my hi-fi anyway so it would be ideal. But for £1000 it's pretty underwhelming considering what I could get with the money instead.