I just installed 19.07.00-rc1-ar71xx and, all in all, it looks good.
What benefits would I be installing openwrt-ath79-generic-tplink_archer-c60-v2-squashfs-factory.bin?
Apart from being a "snapshot" (therefore it cannot be considered rock-solid), how does the ath79 version differ from the ar71xx?
Gui, setup... what exactly?
Just go with the ath79 19.07 RC1 image, ar71xx won't see any improvements anymore, whereas future releases will be ath79 only. 19.07 will be the last ar71xx release.
Unless you have hardware that ath79 does not support yet (or not completely), like a lot of Mikrotik devices, there's no reason to stick with ar71xx. You'll have to migrate either way, whether it be now or with the next stable release.