(This review covers the first edition of Graphic Classics: H. P. Lovecraft, the one featuring HPL as a seafood vendor on the cover.)
As Gahan Wilson points out in his introduction, Lovecraft is one of the most illustrator-friendly authors of fantastic fiction. Not only do his works feature countless atmospheric settings and outre monstrosities, but he can also be quite detailed in his description of said places and things. So, he's a pretty natural choice for a collection of illustrated adaptations.
As if to underline this fact, the first thing after the introduction is a one-page excerpt of John Coulhart's "The Dunwich Horror" showing the death of Wilbur Whateley. It's a great scene, and Coulhart really brings out the full morbid ickiness of it. Sadly, it's all we see of that work, which underlines some of the weaknesses of this collection.
While it has some great, fun adaptations (though more on that below), it often feels a bit of a scattershot effort which seems to flirt with being a better work. Along with the single page of Dunwich, there is a selection of six beautiful pages from Tom Sutton's adaptation of "The Dream Quest of Unknown Kaddath."
Other items are somewhat amusing but flawed. One of the first items is a brief HPL biography, which leans a bit too closely on the de Camp image of Lovecraft as sexually neurotic. (Although I was amused by George Kuchar's fascination with breasts; even one of Lovecraft's aunts has serious cleavage on display.) Another piece, called "The Chaos Rapant" features a rapping, tenticular Nyarlathotep awakening a cranky Cthulhu. It's funny, but seems like it be better off in a compilation of silly Cthulhu parodies.
And though I was happy to see the Fungi From Yuggoth featured--HPL's poetry isn't generally great, but I think Fungi is an exception--the adaptation left a lot to be desired. Every other poem in the cycle features an illustration, each done by a different artist. Some of the illustrations are quite striking, but too many seem to bear little connection to the corresponding poem and opt instead for a sort of general surrealism.
As for the good illustrations, the first story after the bio is an adaptation of "Herbert West - Reanimator." The story has been trimmed down to four parts from six, with each part given a different illustrator. My favorite was the third section, done by J.B. Bonivert, which really plays up the twisted humor of the original; all of the chapters were quite good, though.
I also really enjoyed the adaptation of "The Cats of Ulthar," by Lisa Weber who's done good work in other volumes of the Graphics Classics series. Her art here really captures the sense of dark fable from the original story.
There are several other good pieces, including the adaptations of "The Shadow Out of Time" and "The Terrible Old Man." Luckily, it appears these were retained in the second edition, along with Cats and Herbert West, so I'd more strongly recommend checking out the second edition, which features Cthulhu on the cover.