Hi Mario
I personally have not had any problems with Nortons and am a avid user of it.
I can only talk about it to 10.3.9 (with all updates).
I have it loaded on....
400mhz B&W G3 Rev 2 (687meg/180gig(2HDs))
350mhz G4 'Sawtooth' (640 meg/200gig(2HDs))
Dual 1.42mhz G4 'FW800' (2gig meg/420(4 HDs))
I have had absolutely no problems with it and use it at least once a month when I do the 'housekeeping' on the Macs. I have used Nortons since 7.5.3
As for using Nortons on 10.4.x, I would be hesitant, but would experiment with it.
As from March this year, Symantic are no longer supporting Norton Utilities.
Ron