I've been through multiple generations of the Factory/Work jeans from Origin and they keep getting better each time.

The flex is noticeable and definitely adds comfort, but the jeans still feel heavy duty and tough like you're used to having for work jeans. I have the Deltas as well, they are purposely lighter denim and more stretch, they both have their purpose.

The seat and thighs are fitted closer, so these also pass for your night out jeans too. I run cowboy boots with these no problem, plenty of room below the knees. I've not tried the bootcut version of the straights, but I do have the relaxed fit. Straight and relaxed feel roughly the same below the knees, but the relaxed has some more room in the seat and thighs, but not too baggy.

I'm 6'3, 240lb athletic build and run with the 38 waist/36 length. I appendix carry, and am between the 36 and 38 waist so I always size up.