Don’t be fooled by it being free, it’s excellent.
Great FX are fundamentally about transforming sounds and I wanted a particular thing from a delay/echo, so went hunting specifically for an app/Audio Unit that would do two echoes in a row as it were. This does more than that, but having deployed it now, the only observation is, the swiping of a digit upward on a piece of text (eg ‘fdbk 36%’ sort of thing), isn’t the most reliable or obvious way to dial in changes/settings. Meaning, it’s a bit fiddly at the text size used on my iPad Pro. But this is hardly fair to term a problem. All I did was get into GB with a synth track, and put this to work, tweaking the mod wheel as well, and making the two echoes/delay be 1/8 and 2 respectively. Ratcheted the feedback of both up to 40% or so, give or take, and did a few taps on the keys. I rather liked the result, so this for me is a 5-star app and I even sought out the tip-jar after it. This is a very good effects app, that happens to be free, put it that way. Good job.