OK, so I give it a try for the first time since I switched back to non-free OS world (many, many years ago).
The good: it is about 1 million times faster and more polished than 1.x iterations.
The yummy: the perspective of writing macros in Python instead of craptacular VBA
The puzzling... and maybe the ugly: I have yet to find a way to set OOo locale to "system locale".
Microsoft did a pretty good job with the regional settings, allowing for a lot of customization. Very useful for people who juggle with around 4-5 languages on a daily basis (with accents, chinese characters, and other oddities) and like to have a very customized "common ground" locale. I like to be able to write my dates ANSI style, separate my 3 digit groups with spaces, count in meters, use $ as a currency symbol, and then some.
It is just natural that an office suite should inherit all those settings from the OS (or at least provide a setting to do so).
And so far, it appears that OOo does not have this basic functionality? The "default" option actually sets the application locale to the same used for localizing menus (i.e. if the application menus are in en_US, then the standard en_US locale - including units, date, number formats) will be used...
Looks like I am stuck with Excel for quite a while then.
Fast, cheap, good: pick two.