There are a lot of very reputable outfitters/guides in Maine. I would not let this one bad experience impact your decision to try Maine again. If you want to bag a black bear, no state can offer you more choices and a better chance at such an affordable price.
Picking a guide/outfitter requires some research. Things like calling former hunters on their reference list, talking to the local game warden, talking to the bear biologist for the state about the area your considering to hunt, looking at harvest stats published by the state for the area your considering, how long has the outfitter been in business, how many bait sites do they run, ect, ect. I could go on for a long time on these questions.