I have one from Haunted Memmories and its very good, and I've seen basically the whole collection in person. They're all very good, though I can't compare to other companies because i haven't seen others.
I'll put a vote in for haunted memories as well. I seen the other portraits at a halloween store in the mall and at Spirit, and just was not impressed. Of course, haunted memories are a little pricey but they are worth it. I bought 4 pics from them in 2006. I also found a cheap internet frame supplier so I bought some really old style frames which make the pics really stand out!
I used morbid indust. this year to get mine from, they seemed pretty well, i had no concerns or issues with them and no complaintes from buyers. I'll use them again, but will check the others u guys made mention of.
Above was the folded sales tag it hung from, so I tore it apart to scan it. It reads www.take-1.com, but the site is under construction. The tag reads "Item 597234 HALWN Mutation" . I bought several after Halloween at clearance- roughly .50 ea.
Yeah, I'm kinda a cheapskate out of necesity. heh I also got two fiber filled latex skulls that are larger than a person's head for a total price of 2.50 on clearence and the giant garage skull and hands for 75.00 on sale.
i got 6 5X7's off ebay from some misc seller for 50 bucks. The pictures turned out great. I havent seen them anywhere else. The were the big hit of my party. I added some great clearance frames from hobby lobby and shazzam instant antique. I did also get a couple of the walgreens ones. I took them out of the crappy frames they were in, used a cheap white mat covered with black fabric and a cheap black frame and they looked great.