I've used ForkLift for a while but then I got a notification that Transmit [1] was updated to version 5 and it's been great so far for me. I like the UI more.
Didn't see any mention of SCP -- do you happen to know if that is or is planned to be supported?
Please file an issue :)
https://github.com/marta-file-manager/marta-issues/issues
[0] https://binarynights.com/