I'm seeing mixed reviews for the Peavey AmpKit LiNK and Griffin GuitarConnect Cable, but I'm also seeing reviews that have stated they've switched from the AmpliTube to the Peavey or Griffin, which to me means there's something "unsatisfactory" with the iRig, that's not showing-up in reviews; however, the only thing I can track-down is that it seems to be an issue with crosstalk (feedback) when using high-gain models with headphones that need the device's output volume turned-up to get decent volume.
P.S. OK, found some negative reviews of the iRig -- Yup, the problem is the crosstalk/output volume.
EDIT: Some of the other options:
- Sonoma WireWorks GuitarJack
- RapcoHorizon i-BLOX
- PRS GearBud