I'm a Line 6 user since 1999, when I bought the first POD: I went through the red bean, the Pod XT, the Pod HD500X, and now the Helix. For this reason my review might be biased but anyways I'll start off saying that the Helix to me it's the best guitar processor available today, and it's not (mainly) about the sound.
I've been a touring guitarist, producer, and studio musician for almost 20 years now and I always had the need to have a great range of tones available in a conveniently portable way: for this reason when Line 6 came up with amp modeling I jumped on it without thinking. Even if I'm a Line 6 fanboy I'd say that the first processor that actually got me to the point of not carrying an actual amp around at all times in the studio was the HD500X (it was good enough-ish), but even then I could tell the difference with my hands even more than with my ears.
Enters the Helix.
The tone quality you can get out of that thing is superb, right there at the top with the other big modelers on the market (I checked them out myself and they're all beautiful machines in their own respect) in terms of both sound and "tactile" feeling. That's all I will say about the sound.
What made the difference big time for me are the "side" features: user experience, audio interface, midi control, variax integration, desktop patch editor. From the second i plugged it in my computer usb port everything worked as I expected to, the setup has been a breeze, and the routing made complete sense.
The same afternoon I got it I've been able in just a few hours to setup both my live AND studio setup: main monitors, "boombox" monitors, record without latency the processed and the reamping tracks all without a single glitch, in a super smooth workflow that needed me to look at the manual no more than a couple of times.
And more: I've been able to setup a patch with which I control all my live set, including a laptop with sequences, guitar patch switching with program changes, a processed microphone, and various snapshots..all neatly labelled for clarity to control everything with my feet, without a single hiccup or dropout in sound, and it all worked as expected!!
The Helix has been an absolute joy to program, it has become the command center of my setup both in the studio and on stage, and it has exceeded all my expectations in terms of functionality and ease of use. I can carry it around in a backpack and it even sounds excellent..
Negative point? I wish the included USB stick were larger.
I'll close this fanboy review saying that the Helix gave me the same feeling of amazement I got when I demoed the very first Pod in a shop in NYC almost 20 years ago, the same excitement that got me to write this review, something I actually never do.
Looking forward for the plugin version, keep up the great job Line 6.