i have the ISI with the Rapid Infusion kit.
I have found that blanching green herbs then blending with oil, resting for 2 days and then filtering gives a nice bright green heavily scented oil.. but the ISI gives a rather mild infusion. I personally do the traditional method and follow up with the ISI just to put the gun to good use but to be honest its not the best application of the science... I have found that popping some chicken strips with some light soy sauce into the canister and doing the shaky-shake makes the soy penetrate the chicken within minutes and then I just toss the chicken through some potato fecule, rce starch, or sweet potato starch and deep fry for some really tasty quick and easy Taiwanese Fried Chicken
so if your looking for intense flavor and colour is wanted then stay with traditional methods, but if you desire an oil that is mildly scented, and has no colour infused then the ISI is a good choice.. or to superspeed marination of a small amount of meat etc.
also to be aware of is that the recipes on the ISI website can have multiples with same title and picture but different ratios for ingredients, and the app gives different recipes again, so just because the recipe is on the website or in the app does not automatically make the recipe correct, or suitable for your purposes, though it is a good reference point to start experimenting and come up with your own end recipes.