Is LibreOffice *THAT* bad? :(

[kitepilot at kitepilot.com]

So I talked my brother into ditching Micro$haft and moving to Linux.
Baaaad idea... 

The man uses Excel *HEAVILY*, and LibreOffice just could not keep up.
But it was not lack of features or limitations, it was *STUPID* (but 
dangerous) things like cells not showing the real value and/or recalculating 
wrong. 

I didn't take his word for it, he showed me the (unbelievable) problems (I 
could not believe what I was seeing).
The guy is back to Excel...
What am I missing?
ET