What have you heard about it> Should I upgrade?

I upgrade. On Day 1 Chrome was just draining the battery, switched over to to safari and had no issues.

Make sure any programs you use all the time are upgradable and work.

Example: I had Parallels for Yosemite and had to upgrade for $50 to be completely compatible with El Capitan. In the beta before they fixed it, I could never export movies in Final Cut Pro because it would crash.

Other than that, most of the common programs should work. I haven't experienced any bugs and I'm a HEAVY Mac user. Nothing really noticeable on the outside except for the new San Francisco font. Lots of bit behind the scenes performance updates such as Metal for better graphics processing.

Do you by any chance use MS Office stuff?

I read on the reviews that they kept shutting down when in use.

Because of school, I use those exculsively, pretty much

I had Office crash problems with 10.9, but not as much with 10.10. (I've forgotten what 10.9 was called).

I had Office problems. I had to install an older version of Java to get Word, Excel, etc to work.

Also, Outlook is toast until an update is released. Something about retrieving emails from our enterprise server. When I open Outlook, I just get the spinning beach ball of doom.

I'm holding off for the time being. I think I'm gonna give it a month to let 'em issue any needed patches. Don't have all that many programs on the computer outside of Office, but I'd rather let someone else discover the bugs.