What happens when the ten minute limit is reached in 4K60* - does it overheat, do you have to wait half an hour or a set time, can you just start a new clip immediately?
Photography aside, if this didn't have 4K60 I don't think any Panasonic owner between a GX80 and a GH5 could possibly be interested.
But it does have 4K60*
And it's £200 cheaper than the GH5.
I'll wait on a definitive list of pros and cons after it has been out for nine months and take another look. By then, it will drop another £500 and might be tempting depending on what Sony come up with - which will likely be not a great deal unless you are a pro as opposed to a hobbiest.
I suspect that the a7S3 will not have 4K60. If you want that, you'll have to go high end.
*4K50 in the UK