Easy way to adjust the waistband? It's no easier or harder than on a pair from Epaulet---just take it to your tailor. The goodness of fit is entirely personal preference. I have trousers from Unis, Epaulet, and Howard Yount. I'm not sure there's anything to recommend any of them over the others besides your personal preference for fit, fabrics, and details.
Gios don't have a split waist band or any allowance for increasing waist.
I don't expect a fashion chino to have it at a $100 price point but I do at higher price points.
Fit is nice on Gio's but I'd expect anyone posting on this forum to have a good relationship with their tailor and as long as the rise and the seat look good you can always taper the legs of another brand a bit to achieve the same.