If you want to go back to him with a factual list of problems, I'd say:
1) There should be no visible gap when joining two worktops, only the seam line from the different patterns meeting
2) Adhesive should not be visible along the join - it being visible means too much has been used
3) The profiles don't match. If you look at the one in the left hand side of your photo, if that was properly seated it would move up and right, at which point the profile of the right hand piece wouldn't meet up properly with it
4) At the end of the straight run there is a curve, presumably where the jig has shifted and the router bit has cut a wobble into the worktop piece
I would also inspect underneath to ensure he's bolted it correctly. You should see 3 recesses that are like a rounded bowtie, or dog biscuit shape, with a bolt in each pulling the two pieces of worktop together.