SIR1 is free... and I have it. But I didn't take it into account as I have much more reverb impulse sets then the amount of reverb plugins I tested here.
I see SIR1 (or another impulse player, have to test some I think) as another tool (as you can load other impulses besides 'reverb'). It is in my arsenal but it's certainly not the first thing I go for when I need reverb
... although there are some really jummie sounding reverb impulses floating around on the net
