There are a lot of trade offs.
For something like hermit crabs...these ship REALLY well. What members of the club have found though is that many of the local shops will run ocassional specials for us, and deliver to meetings, and that makes the cost less than online (unless you are ordering huge quantities) when you consider the shipping.
Snails I believe to be much more sensitive shippers. However, sometimes local stores do not aclimate them carefully, so they may be doomed even if you are careful with them. If a sponsor runs a group buy though they are probably dealing with large volumes, and I think are more likely to be careful, or just not handle them as long (their order may come in just before the day of delivery).
For fish it's a trade off. Oftentimes it's hard to get the unusual fish at local shops, however, if you talk to local shops sometimes they will order such fish for you, and even make sure they are eating before you pay the $. It can be a bit more hit or miss than the large on-line shops though getting these unusual species. Some shops have much better connections than others. For sensitive fish you have to weigh the benefits. For fish that have unusual feeding behaviors, some shops may not be able to deal with them. For fish that are finicky, sometimes it's best to get from a shop that's had it on hand a long time and it is now eating. Then there's the risk of disease. Some shops run copper all the time, and that could be a good, or bad thing depending upon the type of fish you are interested, and how careful they are about maintaining the levels. The nice thing about fish is that provided the fish is healthy, there is not a tremendous difference in the coloration of one specimen of a species compared to another.
Corals however are different. There can be tremendous variability from colony to colony of the same species, and usually no one can really id to species level (or even genus sometimes) anyhow. I think a lot of times the colors that you see in photographs are not realistic (taken under actinics), or they may be showing you a photo of a colony that looked great when they took the photo, but has become unhealthy in the meantime. The other thing you need to keep in mind is that the photo may only be showing you the tips of a coral, and might not mean that much when the colony is grown out in your tank and you are looking at it a foot or two back from the tank. I've purchased a few great corals online over the years, but also some real dogs.
