Words can't adequately describe how wonderful the Mauna Lani is and how much I love it there; put it this way: I have been there 3 times and am making plans to go back a 4th time during Easter next year.
It is an older hotel, and there are some things that probably should be refurbished. However, the ambience and the service more than make up for any lack of "grandeur" in the room furnishings (besides, if you are actually in your room long enough to be bothered by this, you have other problems!). Also, in these times of economic stress, the Mauna Lani still doesn't charge a resort fee, nor does it charge for 99% of the amenities that most every single resort on the big island does!
When you first arrive, the staff doesn't check you in at the front desk' they sit you down at a private desk, offer you (and your entire party) a washcloth to refresh yourself and also offer you a glass of cold juice. Everything is accomplished quickly and discreetly.
I absolutely love the valets/bellmen - they make an awesome first impression of the resort, always laughing and joking and smiling and going out of their way to help you. If serious and somber is what you prefer from service staff, this is not the place for you!
A lot of people complain about how expensive it is to eat at the restaurants there; well, let me tell you: Hawaii as a whole is expensive, period. While it is a little bit cheaper to go to the local market and stock up on some basics (there is a small refrigerator in every room at the Mauna Lani), it isn't *that* much cheaper and it is still a lot more expensive than what you would pay on the mainland for the same items. You can find some local restaurants that are absolutely delicious (Huli Sues's in Waimea is one), but, again, you're going to pay a lot more than you would pay on the mainland for the same food. It's Hawaii, it's expensive - be prepared.
I love it, love it, love it! I can't wait for next year!