Technically Beta isn't an acronym for anything in particular. It's simply a phase of software that's released to a selected group of testers after the Alpha testing phase, which comes after the Pre-Alpha phase which includes the initial development and design. Once something has been released to Beta, it's features are usable, yet bug-ridden, hence "Beta Testing."
Then sometimes there will be an 'open beta', which is what Chrome is currently at. This lets anyone who wishes to test the software to use it in this unfinished state and find/report bugs.
After open beta, RTM(Release to Manufacturer or Market), then GA(General Availability).
Personally it runs great for me. Every now and then it will have his issue where a certain webpage will just stop loading, and it'll just start working again later on, but it's not often enough to be an annoyance.
My only problem is when search from the homescreen, it goes to chrome and it won't actually proceed with the search, but it just sits in the address bar.