Got the EHX 1440 in the mail today. Works pretty great, seems very consistent about tempo and cutting the signal out at the right point. Having 2 layers easily accessible (where you can undo the last layer by holding loop for 2 seconds) is nice.
With the pedal on my master output, its a bit of a juggle making sure to cut out your signal as soon as the bar ends, but definitely doable. I may end up doing something similar to what @depuratumba mentioned and putting the looper before a crossfader/mixer with my dry signal.
The vid starts kind of abruptly, I start by engaging the loop, waiting for it to start and then record a bar (blinking means its waiting to record) and then as soon as the loop end I cut out my synth trak.
Edit: been noticing some timing issues letting the loop play out… might be my midi source though.