Thank you Peter for good news! I am surprised since you recently mentioned replying to my inquiry that this product is retired (which it is).
But since you brought it up, here is a question: Would v1.54 support Indigo RT4.0? There is fundamental difference between RT 3.8 and the latest RT 4.2.14
To the speed question (and this is purely about speed - sampling of the same object). As it stands now Indigo RT 4.2.14 (which is not fully supported - again as of now) would beat Iray hands down.
Indigo supports water, speed-trees (to some degree). On heavy loaded scene with a lot of trees it crops out though. Does not support popcorn. And there is a whole lot of other things that RT 4.0 does not support (or rather iClone does not export it properly mapped)