I received the cancellation message for the subscription today, and I am actually quite disappointed, because I have not identified a suitable alternative yet.
I neither find Cryptomator nor Tresorit nor other products as really convincing, because the security always depends on the strength of the password. In the case of Cryptomator, the encrypted masterkey file (which is protected with your password and contains the crypt phrase and salt for decrypting the actual data content) is stored in the same location as the encrypted files. In the case of Tresorit, pretty much the same functionality is labelled as the 'roaming profile' (which is stored on their server). (No comment on iCloud - the whole point of Boxcryptor was to make this independent of the cloud provider.)
This is a design decision to conveniently support access from multiple devices (especially phones), but it reduces security to the complexity of the password as the exclusive factor.
The developers argue that this is not an issue as long as the password (for the masterkey or the roaming profile) is sufficiently strong and thus prevents brute-forcing or similar password-guessing attacks. This is generally true but omits the fact that an attacker may also retrieve the password with other means.
Boxcryptor had the possibility of entirely storing this information locally, and I did not find another product so far that offers this choice (even though Boxcryptor neither did this by default). The approach has admittedly the disadvantage that you if you lose this information, access to your data is truly lost, but personally I would rather accept this risk than having a product or a vendor storing this information (yes, encrypted with my password) on my behalf.
I just don't see the necessity that this should be the case without even offering an alternative approach - which is separately storing the encrypted masterkey and the actual content / data. Again, I understand the design decision, but I am personally not happy with this from a security standpoint.