Don't have one yet (I actually have a pair on hold right now) but have been doing a fair bit of reading on them. Like you found they do suggest at least 75 gal. or more for a mandarin. It is also recomended to have a tank that has been established at least 6 months to a year to ensure a stable pod population. Pods tend to come and go in the first few months of setup. You also want to avoid other species that will compete for food so wrasses and some of the gobies are out. They certainly aren't recommended for beginners, but are sold all the time by LFS anyway
The latest issue of Freshwater and Marine Aquarium (FAMA) has an excellent article on Mandarins. Also read the "Mandarin Primer" thread on RC in the Reef Fishes forum (it's a "sticky" near the top).
What I am gewtting ready to do is try to train my mandarins on prepared foods based on write-ups from Matt Wittenrich who has succesfully bred them in captivity. He ensures all his stock feed on prepared foods. What he does is keep the fish in a net type breeder trap (found at your LFS) and feeds them live adult brine shrimp enriched with Selcon. Once feeding on those he starts introducing frozen brine. Once they start on those he immediately stops the live and feeds exclusively frozen. He then starts additions of other foods like frozen mysid and pellets as brine shrimp alone are not that great nutritionally. This is the approach I will be trying as although I have lots of pods in my system, I don't want to count on them alone to keep mandarins alive.
Just some thoughts, others that actually have them will certainly chime in.