My wife and I stayed at the Four Seasons Manele Bay Hotel and overall we really liked it. I knew we were in for a good experience the minute we arrived at the very small (one airline) Lanai airport, where (somehow!) the hotel concierge knew who we were without an introduction. They had a van ready for us and three other couples to go to the Hotel where we didn't even have to stand at the Front Desk. I think the Four Seasons way of doing business is definitely being implemented.
That said, one day I took a long walk around the hotel and discovered that half of it is still closed for a complete renovation. There were probably about 50 workers keeping very busy on that, but the noise from that part of the construction was not noticeable. What we did notice, however, is that they are still renovating (my guess is for the next month) the Pool side Grill building, so there is defintely some loud noise by the pool. I'm good at tuning it out, but some folks aren't. In fact, we met one couple that after two nights decided to move to the Four Seasons in Maui.
Food: the daily breakfast buffet (which was included in our package) was great. For dinner, the Italian fine dining restaurant was very, very good and I highly recommend it. Avoid, however, the Hulopo'e Court restaurant. The menu just wasn't up to snuff for a Four Seasons.
One day, we took the free shutle up to the other Four Seasons and Lanai City and had a great time. This is an absolutely beautiful hotel and very quiet and secluded. We also walked all around the two main streets of downtown and visited several very friendly storefront vendors.
Snorkeling: one day I walked down to the beach (about 400 yard walk); they offer free equipment, but to be honest, I should have gone first thing in the morning, rather than in the mid-afternoon. The surf had come up quite a bit and I just didn't feel safe and came back in. I would highly recommend that the hotel hire a full-time life guard.
The pool side service was excellent; they often came around with cold towels, cold pineapple chunks, and spritzes. Also, be sure to take one of the power raft trips: we saw an amazing school of "spinner" dolphins, including several babies only 24" in size. This was an unbelievable experience.
I think a year from now it will be a true Four Seasons experience, but it is a fantastic, quiet location.