Quick thoughts:
* the option to install via a remote ROOT LOGIN concerns me. Having root *able* to log in over SSH is a security antipattern. Having SSH with passwords enabled is one too. Giving the server's root password to a third party is an even bigger mess.
* the encryption situation is not explained well. In particular, it is unclear how exactly data is encrypted during transmission and who holds the keys used for that. It also appears that some features are yet-to-be-implemented, as mentioned in the Security FAQ: "In 2015 we plan to enable data encryption before sending with your own public key." This is of concern especially for customers using BitCalm-provided S3 storage, since the website can download the backup to the user's local storage - and therefore (absent a layer of encryption) read the contents.
* there's a pair of mutually-exclusive statements in the Technical FAQ, in adjacent paragraphs:
"The size of database data should not exceed free space in your /tmp folder."
"Databases of any size may be backed up, because all reading and compression process is done with chunks of data in RAM."
One or the other of these is presumably false.