First of all, both locks are fine to use when doing selfbondage. They are particular safe which means that the locks will always open even in case of malfunction. They are different though when it comes to the application itself. We will discuss the differences as following.
1. Locking principle
The MagBound magnetic lock is self locking. When approaching the metal plate to the electro magnet, it locks itself. Therefore, you won't need much manipulation with partly restrained hands in order to complete the bondage. This is the main advantage of the lock and the reason, why some scenarios such as spread eagle are only feasible using it. As long as the hands can't work together anymore, you won't be able to lock the free hand using the restraint hand. With the MagBound, it gets quite easy and with some practice, you can do it without looking. Just let the metal plate slip over the edge of the lock onto the electro magnet.
By contrast, the ice lock is already locked when taken out of the freezer, so additional gear is needed. The easiest way is to fix one handcuff to each side of the lock using cable ties or a little pad lock. This way, it can be used like standard hand cuffs but which are seperated one from the other at the end of the session.
2. Preparation
The MagBound itself doesn't need any preparation. Only a charged battery is needed for the Magbound to get locked. This is the reason why it is very easy to take it on a journey or to a remote area.
The icelock in contrast has to be frozen before and is not as mobile as a result. Sure, you can use a freeze box to keep it cool, which makes it more complicated.
3. Locking time
Both locks can't be configured to open after an exact amount of time. The locking time of the ice lock varies because of the freezer and ambient temperature, the locking time of the electro magnet depends on the state of charge of the battery and the battery type itself. The overall time can easily be determined by choosing the correct type of ice lock, whereas with the MagBound a lot depends on the availablity of power banks of the right capacity. On the other hand, there is a unique technical solution available for the MagBound: an electric timer which can be configured precisely. In case of failure or wrong programming, the lock will still open when the battery is empty.
4. Safety
Both type of locks have been developed with a maximum of security in mind. Opening is guaranteed. Another risk than the blocking could be the weight of the MagBound. It should not bump on your head or your body, in particular when opening in a sudden movement. In that respect, the ice lock has a small advantage.