I doubt anyone on here is familiar with Heck who appear to sell mostly in Germany.
Hub motors are fairly straightforward so the chances are it's no better or worse than all the rest.
You could consider a front motor which would give you a wider choice of power ratings.
Several makes, but Bafang are among the most popular and their stuff is decent.
A beach cruiser is designed for, er, cruising, so a front hub motor would suit it well.