Love Maui. Comes in a close second to Kauai for us, but it's by a slim margin. That side of the island will have had no impacts from the fire.
Couple of suggestions. I assume you'll get a rental car. I consider it essential in Hawaii. The only exception would be if you are inclined to pick a fancy resort and just hang out there, but in my mind, Hawaii isn't that kind of place. It has those kinds of resorts, but you miss out on so much if you don't get out and explore. We spring for a convertible and I think it was easily worth it. Ignore the warnings about taking the road past Hana. I've done this on three islands, and it's been the best thing on all of them... take the outer road ALL the way around the ENTIRE island. You'll see incredibly different scenery along the way. Do it with a mile by mile guidebook "I still think the Maui Revealed book is the best..." As you drive, it will tell you by the inch what to look for. With its help, we found amazing lookouts, blowholes, pools, hidden beaches and waterfalls that were wonderful, and often had them to ourselves.
Ditto on Mama's Fish House. It's been going strong for decades and everyone still says it's a wonderful meal.
Do your homework on Luaus if you want to do one. It was fun, I'd not do one again. But there are some pretty big differences, so read up on them when making your choice.
We did a powered hang glider ride over by the Hana airport. Definitely a wow moment.
Be aware that you're staying on the rainy side... which means it is green and lush, and the rain feeds the spectacular waterfalls the make the Road to Hana famous, but it means you'll have some rain.
The beaches on South Maui are the better beaches. And law in Hawaii means that all beaches are public, and all have to remain accessible. So use the guidebook to find some of the more secluded ones. You may have more trouble finding a place to park, and the pathway may feel like you are trespassing, but the reward is that you will find some beaches that are absolutely perfect, and you may be the only people there. Just beware, there is at least one on South Maui that is known to be a nudist beach... I found out by accident.
And last, many see Haleakala on a bike excursion or some other early morning tour. Early morning is probably a good idea (and maybe on your first day there when you are going to get up early anyway because of the time change), because it tends to get cloudy later in the day. We actually didn't follow that advice and it worked out great for us. It can be chilly on the top in the morning so be prepared. And lots of people go up for the sunrise so also be prepared for crowds. But, I strongly recommend driving up yourself. The ride up and down is amazing, you pass through every climate zone known to Earth, and I like to stop and look around. Someone suggested to us that the biking thing which is popular can be frustrating. You will be in a group, and that means you're subject to the speed of the slowest rider. Plus, you spend a lot of time looking down at the road, and not out at the scenery. In your own car, a convertible preferably, you'll have a much better view, at your own pace, and you can stop if the driver wants to get a look out without watching the road. We got a mean sunburn on that day so wear your sunscreen.
Have fun, Maui is a magical place.
