So some quick comments. And for background I have flown a mix of business and coach on long haul international flights, so I do have some reference comparisons there.
787 Specific:
I honestly didn't feel a huge difference in the way I felt after the flight. Perhaps my nose wasn't as dried out as some other flights, but I still felt "dry" about half way through the flight. I did like the larger windows and the auto-dimming was nice. Since we were flying west we actually had sunlight the entire flight, so it helped keep the cabin dark enough for sleeping and prevented the occasional blinding that comes from someone opening their shade mid-flight to see what it looks like outside. It did make it feel a little surreal seeing the white clouds and snow capped mountains through a shade of aqua blue. The ride was a bit more quiet than a 777 or 747, and felt smoother, but that could also have been from having good air to fly in as well.
Polaris Specific:
I didn't think there was anything significantly improved over the previous version of United Business, and for that matter really any of the other domestic carriers. They are all about the same with similar amenities. The basic toiletries kit looked pretty fancy but unless you are a lotion connoisseur, not really all that special. Still a tooth brush, eye mask, some ear plugs, tissues, etc. The fold flat seats haven't changed, but are of course nice enough to sleep in. I thought the food was a little better than I've had before with United. The meal selections had a bit more options, and the food quality did seem better.
All in all I would say it was really no better / no worse than business class on any other domestic carrier. It certainly wouldn't be enough to change my mind in which airline I was going to chose, and would still make that based on cost and frequent flier miles. I think the 787 is a neat plane and glad I flew on it, but probably won't go out of my way to find flights that use it, especially if there are other alternatives with similar flight schedules.