6.8/10. This is a really hard one to judge because I absolutely loved the Marshall vs. Ted dispute over the wedding gift/thank you note thing, but pretty much hated the Robin vs. Barney's family plot. The former is classic HIMYM, with exaggerated beats and likable characters doing ridiculous bits for our amusement. Marshall and Ted trying to not so subtly hint to each other about the situation was fun, and did the whole "add context to prior history" thing that the show's so good at. Plus, the reveal that it was Stuart who set off the whole deal, and the drive-by pizza makeup gesture was a nice way to close it out.
On the other hand, Barney not wanting to take sides between Robin and his family is a relatable storyline that the show blew up by turning everyone into a cartoon character. We don't need gratuitous celebrity cameos. We don't need Robin and Barney acting like jerks to one another and/or family members. And we don't need a contrived showdown between Robin and Loretta Stinson. There was the occasional good gag, but for the most part, the latter storyline made everyone feel like mixed up cartoon characters rather than real people, and the humor couldn't make up the difference.