The Helix delays and reverbs do not cut through as well as some of the outboard you can get, and they certainly don't cut through as well as the Fractal ones do. I've denied this to myself for 6+ years because I really wanted to believe it... but I just can't.
Here's a bit of a scientific comparison - Take the bog standard Simple Delay on Helix. Set the mix to 50% and the feedback to 50%. Send a simple single note stacatto pluck through it. Count the number of echoes you get, and try to observe in your mind a visual line that tracks the loudness of each one of them.
Then do the same with a Boss DD-7 or DD-8 set to regular digital mode.
You'll notice that the Boss will have far more echoes, and will stay present and audible for much longer.
Okay.... so you think "it's just down to different weightings of the parameters.... maybe 70% on the Helix is equivalent to 50% on the Boss" ..... okay.... do that comparison.
You'll notice the Helix now has more echoes, but still not as many as the Boss. You'll also notice the transient of your pluck gets softer over time in a way that is not related to the drop in amplitube. It sounds more like diffusion is being applied in the feedback path to automatically soften the echoes the more you turn up the feedback.
And most of the digital delays on Helix do this. I can only suspect that the core digital delay circuit they are using has this element built into it and that removing it would break everyone's presets, which is why they haven't done it.
I also think a lot of the legacy delays sound better on the DL-4 MKI than they do on Helix and the M-series effects.
I've had similar observations with the reverbs. But for me the long and short of it is..... I keep finding myself unhappy with the Helix delays and reverbs whenever I use them. I'll be happy for a week or two, maybe a month... but then I compare them to Fractal, Source Audio, Boss, and my Hardwire pedals... and always I feel like there is something lacking.
For the last 6 years I've been using Helix as my primary effects platform for both studio and stage work. And 90% of the reasoning behind that is purely about workflow. The sonics always felt like a sacrifice.
I recall a time where I didn't take my Helix to a gig. I did the gig with my Boss DD-500 (which has problems of its own btw!) and every single person in my band remarked at how much fuller and "epic" my guitar sounded - even the drummer!!
Feels like I'm hating on my grandma right now, coz I've always been a loudmouth proponent of the Helix, but it's time to stop lying to myself. I'm super not happy with it!!