It's quite a bit easier to eyeball than v4, because it's much easier to make sure that your network falls on a character boundary (multiple of 4 bits out of 128

It's quite a bit easier to eyeball than v4, because it's much easier to make sure that your network falls on a character boundary (multiple of 4 bits out of 128) than it is to make it fall on an octet boundary (multiple of 8 bits out of 32). If you find v6 harder than it's just down to a lack of practice.