"Amazing Spider-Man: Ends of the Earth" is a one-shot tying-in to the current Spider-Man storyline of the same name. Containing two pieces written respectively by Rob Williams & Brian Clevinger (with Thony Silas providing art for both), the issue tells the stories of Spidey's global resistance as they aid his fight against Doctor Octopus.
At first glance, there's not a huge amount going on here -- just a couple of story holes being plugged that could just as easily been taken care of in a panel or two (indeed, exactly that was done in the parent series). Still, a storyline with a global scale necessitates the intervention of global heroes and that's what this issue helps to do. After all, if someone's taken over the planet, it needs more than some hand-waving "the Avengers are off-world" to explain why Spider-Man's the only one capable of ending things.
Rob Williams' Union Jack story is probably the better of the two, spending a fair amount of time establishing the stakes and giving us some good images that sell Union Jack as something other than a slightly less interesting Captain Britain. Brian Clevinger's Big Hero Six story is fast-paced and kinetic, but with an entire team of rather obscure characters to introduce and use in only 14 pages, it doesn't really manage to cram in all it needs to.
Silas' artwork echoes much of the expressive, larger-than-life look of the current Spider-Man artists, offering work that's technically competent and consistent, but not showy enough to be the book's selling point. Silas' layouts and composition are better than average and his work certainly has potential, so it'll be interesting to see what he does with "Venom" when he draws an upcoming arc and has a bit more space to show off his storytelling and subtlety.
Ultimately, though, this is the sort of book that suffers from its own editorial mandate. We know going in that it doesn't really "matter" due to events in the parent title, and these characters are so obscure that there's no time to make a wider point about them, because the time has to be spent on telling us who they are in the first place. Williams has a fair stab at writing a definitive Union Jack, but when he's acting as a bit part in a Spider-Man story, that approach can only go so far.
Still, while the stories themselves may not be literary high points, we must give credit where it's due: this is Marvel trying to give exposure to characters who wouldn't sell under their own names in the hope that something might click. If you're reading "Ends of the Earth" and want to see more of that story, there's certainly nothing that'll make you feel as though you've wasted your money. But for the most part, it's a pair of sub-plots surgically exorcised from "Amazing Spider-Man" and given a zombified existence in their own comic.