The setup was relatively easy. I just bought longer bolts for my chainrings, spacers to push the new one over slightly, and stuck the extra gear on the side. I flipped the 3rd gear backwards because I thought it would help with spacing, in practice it seems to be a straight-cut gear so flipping it was useless. I raised my derailer to accommodate the new, larger gear, and adjusted the limit screw to allow it to swing wider. Other than that, I had an MTB friction shifter I cannibalized, this system does work with normal 3-speed shifters though you have to compromise by tuning it so two gears get one click on the shifter.

I live in a very hilly, windy, dirty, pothole-filled city, so the ability to widely and suddenly change my power is very useful. I have this set up as 24-34-42-48 in the front paired with an 8-speed 11-32 in the rear, because my bike came with the first 3 but I found the 42t too small, so I got a 48 to upgrade but didn't want to loose the range.

Every single gear has been extremely useful in it's niche. I can get into theory but I have access of almost every gear combo, almost the full 32 combinations. And these 32 gears are very widely spread, yet have plenty of precision over that range which seems to be the goal of modern setups. That new 11-speed Shimano system that they were going on about that has 500%+ increase in gearing, mine is pretty close to that. My highest high is 48-11, and my lowest low is 24-32.

As for cross-chaining, my chain is by average much straighter now, since riding to the extremes of my cassette is even less necessary now. First gear can get from 1 to 6 (on my 8-speed cassette), second gear can get from 1-5, third gear can get from 3-8, and fourth gear can get from 4-8.