There is a reason they offer the guarantee. You don't get to see the fish, not to mention not getting to see if it is not eating, hiding, etc... In addition, you also have the stress of additional shipping. (one of the main reasons for the guarantee) Plus, unless you are buying over a certain amount, the shipping costs on some of them doesn't make it worth it. Plus, you are helping support the LFSs. I'm certainly not saying don't order from them because depending on what I'm looking for, I would too...However, usually the cons outweigh the pros.
BTW- CPE offers a guarantee I believe