I wrote a bit about this a year or two ago.
Suspension forks on commuter bikes - Bike Forums
Briefly, nearly five years ago, I had a full suspension MTB with a really efficient rear end, and I was sad to sell it for a more utilitarian hardtail. Two years ago I lucked into a screaming deal for a slightly trashed top-level DVO Diamond fork for the hardtail. Now I'm pretty much spoiled. I could go for the idea. But whatever it is, it has to work well. I'm not going to buy something just because it looks like it might make the ride more springy