I liked this episode, there was a mystery, more details in the plot, more for Hoshi to do.
The floating coffee cups and bowls of food was cute but unexplained. Why did the phenomena last for so long, but only in one place in a room, even though the ship was moving at Warp or at Impulse?
The spheres are ancient artifacts so have nothing to do with the Xindii, but sound as if they have a lot to do with the Expanse itself. I think it was said that they were made of poly-Duranium alloy and that it was similar to the Pirate vessel's hull. Did this mean that the sphere builders and Pirates were somehow related? Or simply that poly-Duranium alloy is the de rigueur material for Starship hulls? I think it is the latter, another nod to the future, since Starfleet later uses Duranium hulls. On the other hand I've read online that it was Trillium-D, but that's not what I heard.
The aliens, who Phlox identifies as Osaarian, were pretty ordinary Star Trek forehead and nose-pieces with pony-tails. It's like they sit down and think "What haven't we used before? Oh Yeah! Pony-tails! that'll do this week." Why not reuse someone like the Pakleds instead? They were pretty stupid but mechanically minded and would have fit the part, plus they looked almost the same. (Apart from the pony-tails.)
It wasn't said, but I read in an magazine interview that the Osaarian taken as prisoner was meant to have been caught in an anomaly himself and that's why his face got twisted.
Is this the first time they follow an ion trail to catch a ship? Again it's something Jean-Luc Picard later would do on an almost weekly basis.
And it ends with Archer about to learn the secrets of the captured Xindii database.