i think SR shows kind of a Constrictor with a Turn before the final tuck of the Bitter end under the Standing Part. So would seem even more secure by less tension in the Bitter end and same in trapping Standing Part, and still the ends stabilized squarely.
i like for general purposes, where shown in the Snuggle's picture #1 almost makes a Clove; i take that path; except don't follow the arrow. Instead of following the arrow under, take it over, then tuck Bitter immediately into the same final resting place as a Constrictor, or as shown in this picture set for the Snuggle. This gives the same immediate trapping of the Standing Part force on top of the low tension Bitter end to secure, and the same center stabilized position of both ends. Easier to untie than Constrictor, less line and fumbling than Snuggle as shown; and very secure. Any of the 3 will take load well from either end/both; but only the Constrictor is truly symmetrical as i see it.
i wonder if a Double Constrictor would be more secure than this Snuggle form? Each adds a Turn to a Constrictor, but in different ways.