I have been searching (for a long time up to about 2 years ago when I found FreeFileSync) for a utility that does this, even contemplated creating my own. FreeFileSync is a one stop solution that does it all, and does it the way I expect it to. And its versatile and user friendly enough to compare files produced by the engineering tools I use. I've even used it to check disk transfer speed in real life scenarios, works like an absolute charm.
It really became a tool I use extremely often, it's one of my must have's like 7zip. It beats "Unison" hands down for user friendliness and speed to install and get on systems. It beats the tool "Beyond Compare" hands down because it's open source and freely available, but I have to say, I'd love the "Beyond Compare" capabilities, but I cannot justify its cost. FFS does enough for me that I can do without it.