I'm leaving a comment rather than a starred review as I don't want to drop stars for what must be a very edge case: I use Serial to connect to single board computers running (very) old operating systems, such as CP/M-80 and CP/M-68K.
First, let me say that I love the integration of the drivers so that I can connect to the boards without having to install anything extra. As others have already commented, this makes this app unique and great for admins. The bundled Kermit, XModem and YModem etc for sending and receiving files is also great. These two combined is why I bought the app.
However, there appears to be a bug in either the CP2102 driver or the bundled Kermit - whereas on my Windows laptop with Terraterm I can transfer files without problem, with Serial nothing but the smallest (1-2K) text files will transfer. Sometimes even not these. Kermit eventually times out on the board end and the file is there but 0 bytes. Unfortunately I paid for the app after testing just the smaller transfers which worked for me that time.
I should say that the actual terminal emulation over the serial to USB connection works great - it's just the send/receive file part.
I've sent 2 support requests to the author but have not heard anything back - not sure if the help form works or not.
So, just in case anyone else has the same use case, be aware of these issues. If you are doing work on something slightly more modern it sounds like you should be more than fine.