Chrome repeatedly and suddenly crashing.

Not seen Chrome crash at all, safari yes, several times a day spinning beach ball.

Chrome freezes for me and requires Force Quit almost everytime that it is closed.

Chrome Version 51.0.2704.106 (64-bit)

I would like to point out that everyone should check which websites they have open, as the crashes could be caused by a badly designed website (or worse), perhaps trying one website at a time, or adding one website at a time until the bad website is found.

P.S. I haven't yet had an issue with Safari or Chrome crashing in macOS 10.12 Sierra Beta.

Might want to check /Library/Logs/DiagonosticReports/ to see what's being dropped in there by Spin Report. If you're having spinning rainbow cursors coming up a lot, this might give you some indication of what's going on.

It's how I just learned that RescueTime does not work and play well with Sierra yet, and things have been running much smoother for me since quitting that app.

Chrome is having a lot of issues on Sierra but Google is working on them. The Canary build is what you should be using on Sierra as the stable build will likely not get Sierra updates as fast. You can see all the Sierra bugs and even submit your own at https://bugs.chromium.org/p/chromium/issues/list?q=label:Hotlist-Sierra

Chrome Dev build contains the fix & it will be released in the new Beta today or tomorrow & the stable later in July. The problem with Chrome on macOS Sierra was the Blink Fonts. Webkit fixed this issue earlier this year but Google did not get the message or fix so it is now fixed. I'm actually typing right now from Chrome Dev build and I personally think it uses much less memory than before because of this new fix.

Same here: Chrome freezes about once per hour. No other problems.