FTPeel is the Winner!
OK, in the saga of the FTP SSL/TLS problem I've come to a wonderful find. FTPeel from Freshly Squeezed Software in FL has an SFTP, FTPS, FTP client that looks as nice as Transmit. It doesn't have the "your stuff"/"their stuff" two-pane approach, rather it has a single view on the remote data that you can download, edit and upload. It's clean, simple, and works perfectly well with Comcast and that's all I need.
Seems like a lot of digging to find this, but now that I have, I'm an owner and that means great upgrades, etc. Gotta love that.