There doesn't seem to be much info on the I-ray characteristics vs R72, other than it claims to pass 700-1100nm compared to the nominal 720+ of the R72. So in that respect I'd suspect they're going to be very similar.
Also, just for info, I have recently bought two unbranded R72 equivalent filters from ebay, at under 1/3 the cost of the Hoya original. Side by side, I can't see any significant difference in the camera IR output between them so far. One of them does appear a little brighter by eye. So if people want to get in on the cheap, the unbranded ebay ones seem just fine. I'll write more on this later...
_________________Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.