I tend to use the Normal channels more than Bright because on those real amps, that's the channel I used. Tweed Bassman, Plexi, etc. I found that my guitars, pedals, desired tone, etc were much easier to achieve via the normal channels. The bright was too strident and "fizzy" or "buzzsaw"-like.
So when I got me Helix (only a few weeks ago, I'm a newbie), I tend to use the "NRM" versions for the very same reason. I lean toward Cleans and Classic-Rock-style overdriven tones, and the NRM versions just seem so much easier to dial that in. There is still too much fizz and "spittiness" in the BRT versions for my taste.
On the Blackface models (Twin / Deluxe), I go for the Vibrato Channels because those amps tend to need a little more push in the mids and the extra gain stage in the Vibrato channel is definitely nicer (to my ears). I also used Vibrato on those real amps because i wanted to use the Tremolo and Reverb.