I saw a commercial on the Maui visitor's channel while I was on my honeymoon, and this store promised to be the end-all-be-all of Hawaiian souvenir shopping. My husband and I had a list, so I talked him into driving up to this place the Monday of our trip, so we could get our souvenirs out of the way.
Let me point out first that in most instances, it doesn't really matter where you buy things in Maui, they are all overpriced. Yes, a WalMart there does sell a lot of the touristy things cheaper, but I found certain stores to have better quality, this being an instance.
Everytime you walk into a Hilo Hattie, you are greeted at the door with an "Aloha" and given a seashell necklace-lei. The store lays out like a Target or other upscale-fashion boutique. There are TONS of Hawaiian shirts, sarongs, leis, scuba equipment, toys, mugs, paintings, postcards, candies (and for the record, Hawaiian chocolate ONLY COMES WITH MACADAMIA nuts... if you have an allergy, you are outta luck), coffees, trivets... you get the idea. Lots of knick-knacks and more.
Combined with several widely-available coupons, you can get a lot here and get freebies too. On our two trips, we got 5 free mugs, 4 necklaces, a photo-card set, and I think a keychain, free. Which helped out in the souvenir-giving department.
The staff is very friendly, and not pushy. Checkout is quick, very secure (they check ID for every transaction), and the selection is good with lots of good quality merchandise. You will pay a bit more here for certain things than say, the local "ABC Store", but it is a bit nicer of an environment, and you get some nice free things, too (if you spend enough).