Many of the other tie-in comics look and read like uninspired hack work. But there're actually a few I can wholeheartedly recommend. They don't reach the level of 'Fray' but they're still good. Lemme dig around a little...

"Ring of Fire" (Buffy) by Doug Petrie and Ryan Sook: I'd rec this one for the artwork alone, which is really beautiful. Very good likenesses, too (but not this slavish, photoshopped kind of likeness you find in some of the most recent Spike comics). Story is good as well, though Drusilla's voice is off. Features Angelus.

"Haunted" (Buffy) by Jane Espenson and Cliff Richard is written from the Mayor's POV. Post-Graduation. Very good story idea, good artwork, great dialog.

"Illyria" (Angel spotlight) by Peter David and Nicola Scott has spot-on Illyria characterization.

"Reunion" (Buffy) by Jane Espenson & various artists: The backstory behind Buffy's and Angel's meeting when she came back. Now, this one reads like a fanfic, and I mean this in the best possible way. The way different POVs are drawn by different artists is maybe not new, but effective and fun.

There're more that I found at least entertaining, but these are my favourites.