I ordered from Liveaquaria before and I doubt I'll do it again.
I ordered several fish and clams 1 1/2 years ago. Here's my experience:
Some of the fish that made it alright didn't look much like their pics on the website. Some of the Fancy guppies came with shredded fins (could have been an isolated incident). Some fish were salt water fish I didn't order (had to drive across town to donate them to a LFS I trust).
Now the positive. Excellent service. They had no problems making it up to me. One part of the order made it just fine... my clams. They gave me store credit for my troubles (see above) and I purchased some more clams, which also made it fine and were very healthy.
I'd only recommend buying from them if you really can't find it anywhere local to take a look first hand.
I almost always order goods from drsfosterandsmith.com. I've always had good service and shipping was always on time.
as for liveaquaria, I've ordered from there I think 9 times, and service was always good and on time. Of all the times, I never had to pay for shipping because my orders always exceeded a certain amount.
I'm glad to have read this thread because we have just ordered both fish and plants from them and are waiting for our delivery date to be emailed to us. I was wondering all those things that have since been answered in this thread. Thanks everyone!
I was looking at purchasing some livestock from them and having never done that on-line before, I called them. They seem really friendly and knowledgable. I think their shipping fees for livestock were quite reasonable since the livestock is shipped overnight. I was quoted $35 for overnight shipping for items totaling up to $250 and then $39 for items totaling $251 or more
I've ordered a pair of fish from them, and didn't have any problems.
They are the only online place I've ordered live goods from, so I don't have anything else to compare them to. But I would recommend them if they have what you want and you can't find it locally.