Spring straps are all similar, but there are differences. One is what covers the springs -- this can be a plastic tube (leaves a fairly hard surface against your heel and can be uncomfortable), fabric (softer, but doesn't distribute pressure) or a broad rubber strap (best for spreading out the pressure, but the ones I've seen have a loop of rubber as well, which one might not like). You also want to make sure that the springs contain some kind of limiter to prevent overstretching. And finally, the method of attachment differs. Some spring straps are set up to snap into the plastic attachments for the original straps, which kind of defeats one of the purposes of spring straps (which is that they don't come OFF). Others require that you remove those attachments and affix the springs to the fin itself, which may require some tool work.
I have Halcyon straps on mine, which have the fabric covering and a limiter, and permanently mount on the fins. But I have to say that the XS Scuba springs have a nice feature, which is a small tab on the strap that you can grab and pull to get them on and off.