Not totally useless, when incorporated with other pedals it can make some interesting sounds. Decent slapback effect and vintage echo on its own. Very cheap quality but it's only ~20$ so what do you expect.
First time I got this, I was so happy to have a sort of delay pedal. Five minutes later, I'm wondering why this thing is stuck on slapback.... Sure, you can make some good sounds, but after a lot of tweaking, the only feasible setting is to set the mix and repeats all the way to make a sort of pseudo spring reverb.
There's only really three or four distinct sounds that can be coaxed from this unit, the fully open echo is great before or after modulation into a hot amp for classic 60's garage and psychedelic sounds. Cooling it a bit it approaches slap back and swish of surf and rockabilly tones but there' plenty of better pedals to achieve that effect. The construction was surprisingly pretty good but getting a battery to comfortably sit in the closed case is a nightmare (there's not enough room). It's only a two knob design so it is inherently pretty limited but functional enough for a cheap easily replaced roadworthy pedal.
It's kind of a weird pedal... I assumed it would be a delay type sound, but all it does is a kind of slapback effect. If you put the repeat low you can get a reverb sort of sound, but it won't sound great.