I bought the Firehawk FX about 8 months ago and I love it, after I downloaded the app on my iPhone It took me about 3 hours on a Saturday to get up to speed with using it.
Regarding lag time when switching from tone to tone: I spoke to one of the guys at guitar center who has a Helix, he told me it has a lag time as well when switching tones.
I love that when you sync your music from your smart device (iPhone for me), you can play a song and have usually at least 15 tones or so (from the line 6 cloud) that others have created which are close and sometimes a match for the guitar tone of the song you are playing, I also love that you can store an unlimited amount of tones on your “tones” setting.
I got together with my sound guy (our bass player) in our band and set up all my tones so that I can push the volume/wah pedal down (forward) to boost the tone to a “lead volume”, this way if we’re playing a song like Hard To Handle (Black Crows), when I play the lead I just push the pedal down, you can use the foot switches on the 2nd row as well but I prefer just pushing the pedal down, less fumbling around in my case.
Our band plays out once a month or so, I’ve used it for the last 5 gigs and I’m not going back to my previous set up (stomp box board).
Bottom line for me is it has everything I need tone wise and operational wise, I’ll use it until I’m forced to upgrade (much like with my iPhone)... which hopefully won’t be for a few years at least.
There are a lot of other great features I like about the fhfx, such as the ease of practicing, (plug your headphones into it sync your phone and run through your bands set/playlist), all without disturbing anyone else in the house.
I could go on, but you all get it, I’m a fan of the FHFX.