Congrats on the jump! I also own the Axe-FX Ultra. It's waaaay awesome, and I especially like the different weird effects I can play with. I also have the MFC-101 controller to go with.
When I bought my Helix a few months ago, I did it as an impulse buy. I kinda discovered it by accident. It's the first piece of Line 6 gear I've owned. I've always liked multi-effect pedal boards and have also owned the BOSS GT-8 and BOSS GT-10. They sounded a little digital, but it was good enough for me, and I thought the sound was decent (not for distortion though). With that said, I'm not really a sound "purist" like some of the other really hard core guys on this forum. I just like really good effects and equipment.
I still like the Axe-FX, but am currently considering selling it in favor of the Helix. What sold me was absolutely the interface, scribble strips, ease of use... I built my patches from scratch. The fact that I didn't have to lug around a rack unit and case anymore, all the wires to connect the MFC-101, etc... I just like the simplicity, and it's an all-in-one unit. I am really looking forward to the ongoing firmware updates, etc... The DSP processing power is definitely waaaay better than the Fractal as well. The reason the Fractal sounds better is because the way the DSP algorithms are programmed, as opposed to the way Line 6 does it. With the POD products, I believe the the modelling was done using something called "piece-wise polynomial functions" mathematically speaking if the value was over this, then this, else this. Fractal takes a logarithmic approach. Not sure how it's done for the Helix, but I think the approach is fundamentally different. I love my HELIX so far! The sound is awesome, and I'm running it through a Roland Cube 40XL (No effects loop), super clean channel. I am also using some Ownhammer IR's.
I dare not compare which unit is better. They're both good. If you can't get a good sound from the Helix, you're doing something wrong.
Check out this interview with Cliff Chase...
http://www.guitarmessenger.com/interviews/cliff-chase-interview-fractal-audio/