We have both here - I refuse to let bigfix/tivoli (tivoli=i love it spelled backwards) touch anything that Casper is doing already (fortunately I've been able to hold off the exec's, though I don't know how for long). We've had IBM/tivoli forever here on the Wintel side, and it's always been a hassle and headache - generally causing more probelms than it solves. Post Bigfix... is too early for me to make a judgement. But based on past history I will fight it until they let me go.
Trend - imo - is one of the worst AV / malware packages in existence. I always joke that if they want viruses and malware on the machines they should install Trend. That being said, it's inexpensive - so price trumps quality in pursuit of the almighty dollar.
All kidding aside, we don't have a huge population of macs (500+ macs vs 60,000 Wintel boxes) - but so far, knock on wood, trend has been easier to manage than Symantec was, and we haven't had any virus outbreaks at all on the macs (pre/post trend). Trend kind of does it's thing, and I haven't noticed any performance hits from it, and it updates quietly w/o user intervention.
