I've only seen them live once. Last year at Rockhampton's ATGD regional tour, which was so awesome, despite the massive storm that wiped out half the lighting, flooded the stage and ruined our local support bands' equipment just minutes before they were suppose to come on stage.
However I can say I have been able to hear them on the two other occasions they played in Rocky. The first was in 1997 (small back-story)there was only a couple of people from my primary school that ended up going to a seperate highschool than all our friends so we kind of stuck together in that first year and anyway none of us could get tickets and in my case there was no way my parents would even consider taking me to this concert let alone could even get they're heads around the fact that their little 13yr old daughter liked listening to this kind of music, so a heap of us had a party at our friends house that was one street away from the venue and we sat in the back yard straining to here Silverchair play. It was the best.
The second time was in 1999 (this time I did ask my mum and her reaction was exactly what I thought... "Since when do you listen to Silverchair, That's not an appropriate concert for a 15yr old girl like yourself... Absolutley not" - Personally silverchair were the least of their worries i was also secretly listening to Nirvana, Marilyn Manson, Slipknot, Metallica and Korn just to name a few - now I gotta say here I. Was. Devastated... especially since my best friend was going with her older bro) So I took a chance at asking to have a few people over that night with intentions of listening to the show from the backyard (we'de just moved into a new house that was only a 10 minute walk away from the the concert venue) to no avail she said no... So in the end one of my best mates that lives behind me and has a three story house invited me over for "dinner" and we sat on his roof and listened to the Feak Show concert from there and despite the lightning show going on in the sky and occasional rain the wind was blowing towards us so we could hear the show perfectly!