Mahana and Maui Kai will give you the best ocean views.
What we like about the Mahana (where we've stayed 3 times) vs. Maui Kai (where we haven't stayed):
You have an ocean view from the pool at the Mahana, whereas Maui Kai's pool is in behind the building.
Mahana units all have in-unit washer/dryers.
Loungers on the grass at the Mahana with palm trees for a bit of shade, whereas Maui Kai has a concrete patio in front with a few loungers.
The beach walk starts next to the Mahana ... to access the beach walk from the Maui Kai, you would first need to walk along the beach in front of the Mahana, or walk around on the sidewalk (about a 10 minute walk.)
Having said that, I think you would be quite happy at either and would check VRBO listings for your dates since pricing will likely be less expensive than renting direct. Both resorts are quite popular and you might find limited availability through VRBO for this fall (depending on when you're going).
Re Honua Kai - lovely resort but you won't have the ocean 50 feet in front of your lanai like you will at Mahana or Maui Kai. Also, rates will likely be higher, unless you get a mountain view. Honua Kai would be a good choice with children, because of the pools. (We're doing a family trip this fall ... most of us are staying at the Mahana, but our daughter's family is staying at HK ... for the pools.)
The beach in front of all of these resorts isn't as nice as it is at Royal Lahaina ... Honua Kai would rate the highest amongst the other 3 resorts for the beach, with fewer rocks in the shallow water than the Mahana and Maui Kai have.
We have stayed at the Royal Lahaina twice in the past two years and loved it, it is located on a great section of kaanapali beach and still in walking distance to Whalers village for shopping and dining (15-20 min walk). Be sure to get a south facing room for mountain, ocean and golf course views.
One additional thing to keep in mind ... some resorts have daily parking and/or amenity fees that you'll want to factor into your budget.
If you rent privately, there is usually a one time cleaning fee, and at some resorts (e.g. Honua Kai and MKV) a daily parking or amenity fee as well. Renting privately at the Mahana (and I believe Maui Kai), there is no additional parking or amenity fee.
If you rent directly thru the resort or via a site such as hotels.com or expedia, be sure to check on their website re additional fees.Edited: 22 July 2013, 16:28
We've stayed at the Mahana once. We really liked the place. It's a fairly small property but it's well kept and away from the hustle and bustle of Kaanapali. The views from the rooms are amazing. The pool and lawn area are really nice too. There is also a Star Market right near there for groceries. I would stay there again in a heart beat! Sorry, I'm not familiar with the other properties you mentioned.
Susan, we saw it a year ago, but couldn't imagine it being torn down (that quickly?) or why MR doesn't show it. Not so say they show every complex, but most of that size are shown. Seems odd.