The Swiss brands are generally considered the best. Instead of a neon green, they are more of a blue-green. A lot of their stuff is home-brewed. The kits you can buy to make your own are generally pretty good. Just be sure to distill the alcohol instead of just steeping the herbs. You can get the strange effects from steeping, but part of drinking absinthe is actually enjoying its taste. Won't happen with steeping. Plus, with distillation, you are more likely to get a liquor that will louche (turn opaque from the volatile oils in the absinthe hitting cold water), which is part of the overall effect of the mood of the drink.
A lot of people order online and have it shipped over (this is how I experienced it). However, many of the European brands are underdosed in Thujone (the psychoactive chemical in wormwood that gives it the additional "umph") due to the fact that too much of it is a neurotoxin. There are numerous brands...Spanish and Japanese generally considered the stronger ones. The most common brand is Hill's, which is generally considered the worst...so bad that it is nicknamed "Swill's".