I don't know about GEOS being bundled (perhaps it was at one point - CBM did like to try and promote the serious aspects - including a C64 printer and disk drive bundle, that I can remember my late Grandad buying) - but it certainly was a very impressive system.
I recall using GEOS on a friends computer, and as i'd been using the Mac Classic at college at the time, was rather impresed with it. GEOS Write and Pait - were certainly not at all bad for system.
C64 users had at least a pretty solid drive system right from the start - and this was ideal.
On the other 8Bit side - although sadly not on SAM (technically possible though!) I did see a CPC running SymbOS at RetCon - which is also available on a few platforms. Very impressive - and yes, it also supports Minesweeper