I like them, but they’re a bit of a faff:
Pros:
Comfiest saddle you’ll ever use, if you pick the right one.
Will last for years if you get a good one and look after it.
They look nice. 🙂
Cons:
Heavy.
Expensive.
Need breaking in.
Need looking after, like a good pair of leather shoes.
Try to keep it as dry as you can (waterproof the underneath, put a bag over it if you leave it outside in the rain, don’t ride it if it’s sopping wet).
The quality can be a bit variable – some last for ever, some don’t. Could just be down to how they’re cared for.
They really, really are remarkably comfy though.
At the moment, I prefer the leather saddles from Spa Cycles:
Linky.
Very, very well built & much cheaper than the Brooks models on which they are ‘closely based’.
Lots of threads on here about them, might be worth a search just to get a wider range of opinion – I’m a bit biased 🙂
If you have the cash, it’s worth trying one just so you can see what the fuss is all about.