I actually just switched a backup script of mine from using a tar.gz to just a regular tar file. It's a little bigger but overall, the process is so much faster I don't even care about the tiny extra bit of compression (100gb vs 120gb transferred over a 1gbit connection). The entire reason I do this is, like you said, transferring files over the Internet is a billion times faster as one file, BUT you don't need the gzip step just for that