Not bad. Certainly not as robust as the Microsoft desktop counterparts, but pretty awesome. I’m now using Sheets to perform financial analysis and after some tinkering and digging today, I feel that I am a moderate level of comfort (which is about where I was with Excel). For example, there are a ton of functions – I certainly do not know all of them:
List of Google Sheets functions
I also figured out how to reference data from another tab within the same sheet (similar to Excel):