This is a very nice introduction to black rings in five-dimensional general relativity. While these rings are solutions to Einstein's equations, they are (both in the thin and the fat limits) unstable, and hence one can argue that their physical relevance is limited. Furthermore, there exist black rings that one can construct in other five-dimensional gravitational theories (constructed in large part by the authors) that bypass this limitation, and have interesting physics. I believe the article can be improved by mentioning the stability issues of black rings constructed in 5d pure gravity, and the existence of black rings in other five-dimensional gravitational theories.
This is an excellent brief introduction to the black ring. One minor suggestion.
In the item "background" it says: This solution is topologically spherical and is uniquely labelled by its mass and angular momentum
Maybe more appropriate to say: the solution has an event horizon that is topologically spherical and is....