I did some training with MLH a few years ago and cannot recommend them enough. The owner, Ben Fouts, runs a great business. He is the DPE as well, and training with a syllabus that is supervised by the final authority is definitely an advantage. The instructors I worked with were very proficient and dedicated and did a great job preparing prospective pilots for commercial type operations rather than just preparing them to pass an exam. They also had a senior instructor (Doug Fronig) that had a good amount of commercial experience, rather than just a 900hr straight CFI. They use a lot of great off airport sites (at least on Oahu) for all skill levels, from SL and large to mountainous and very confined. It was very refreshing to see this in a world of risk aversion rather than risk management... Instrument training in the HNL vicinity is some of the best IFR training I've seen as well; there is nothing like holding over Kokohead VOR in their R22 instrument ship, which is well equipped as well (Sandel EHSI and Garmin 430 IIRC). Their rates were comparable with the mainland US as well. Definately a great place to train.
Mike