I'm in the same boat as recluse with lower-level alts, but also have 11 80s currently (only class duplicated is mage, but one is Alliance and one Horde). Of all classes, though, I think I have more lower level druids than any other class - it's always been my favourite class
I like the variety and ability to change my role or playstyle at will. There are days I feel like PvPing on my feral druid (usually), but other days my elemental shaman comes out for some fun when I don't feel like mauling faces physically. PvE-wise, the feral is also a tank, as is my DK...and both raid. It's quite fun to see the differences in tanking styles, strengths, and weaknesses of each in the same situations. It's also saved me a bit in dual-spec hassles at times.
The downside: it can get confusing with keybindings (I'm not a clicker). Years ago, I started grouping my keybindings by "like function", so things like roots, frost nova, etc all get the same keybindings. Same for defencive cooldowns and so forth. Saves a lot of the shellshock from swapping classes multiple times in one day.