Love our Happy Heiny's!
They make up a large part of my stash, in fact.
Here are my pros and cons. (Easiest way for me to organize my review.)
Pros for most recent design, particularly the solids:
Trim fit that is nice for day use. Narrower through the crotch than FB's. With hemp inserts, you get good absorbancy with a very trim fit under clothes.
High rise and gentle in the thighs. This is a pro for some with babes with long rises and chunky thighs.
EASY, fast aplix closures that stay shut in the laundry on their fold-back tabs. Daddy/care provider friendly. You get a nice looking, customized fit with aplix closures compared to front snaps, IMO.
Usually no leaks. This depends on some factors that I will mention in my "cons" list, but overall, these are one of my most reliable diapers, suitable for even a heavy wetter and long nights.
Come in cute prints.
All microfleece inside. The microfleece lining inside really helps keep skin dry and makes poop removal easier.
Durable. So far, none of mine are falling apart or loosing their waterproofness. I can put them in a 150 degree wash and dry them on hot and they look no worse for the wear.
No wicking at leg bindings or through aplix panel. I can't speak for older designs, but we have had inserts in our solid HH's be completely soaked and the outter does not get wet and it does not leak through the aplix panel in front. Only when the insert is dripping wet and there is nowhere else for wet to go will this diaper leak. And that is as it should be.
Stuffing options. I love that I can use almost anything inside this diaper. You can use a washcloth if you run out of inserts! lol One of the biggest advantages I see is the ability to stuff with thin items like prefolds or even flat folds. Easy/thorough cleaning and fast drying.
Linda is very helpful, professional and nice to work with. She cares about quality and good customer service.
Narrow through the crotch. This was also one of my pros! This can make it more difficult to stuff with certain things, though. For EXTREMELY heavy night wetters for instance, it does not easily accomodate a REALLY huge hemp fleece prefold. FB's are wider, so they are better for us in that circumstance.
High in the rise and gentle in the thighs. This was also one of my pros! :LOL This is a con when you need a low rise diaper or have a baby with super thin thighs. If your child has a short rise, a well stuffed HH can hang slip down off their ribs onto their hips, causing more gaping at the thighs, and give them a bee butt look,. LOL My son has very thin thighs, and we can still use these, but there are some conditions in which this is not ideal (more in the cons).
Aplix closures. Again, this is a pro for some. The aplix is durable and overall great, but not everyone likes aplix. For some toddlers, it makes the diaper easy to remove. Some people have issues with aplix looking less "nice" over time. And it may not hold up as long as snaps. So far, it is holding up pretty well for us, though.
Sometimes leaks under certain circumstances. As I said, this is one of our most reliable diapers. We usually NEVER have leaks. But here are some ways I can gaurantee leaks:
Wash them with the wrong detergent. There is a very long list of things I've washed my HH in that have made the fleece repell. When the fleece repells, the gentle thigh issue comes into play for us. Because it's not a tight fit around our son's thighs, the urine easily leaks out the legs when the fleece is repelling. I only have 4 detergents I KNOW will not cause my pocket diapers to repell, and unfortunately, they either have yuk perfume smell or are expensive or don't clean well. The one that smells great and works great is super expensive (Amway SA8 Sensitive) but I'm a detergent nut, so I keep trying new things out. So this con means that these MAY be difficult for you to care for to keep in good working order. Especially if you have a baby with thin thighs and haven't found a detergent you like that doesn't leave residues.
We also had some mild wicking to the outters with the PUL prints. They didn't do well for us overnight. I only use solids now because of this. The prints are a little too heavy and stiff for my personal taste, as well.
Synthetic. Well, most of us know that synthetics hold on to odors and don't breath well. Some kids are even sensitive to synthetics or fleece against their skin. If you wash frequently (every day or two) or don't store them in a stinky dry pail, you shouldn't have too much problem with stink, though. And so far, I have not notice my son being excessively hot in these, either.
Must wash after use. Unlike most covers, you can't hang it up and use it again a few times. And that makes them a little harder for some to afford.
Many of those cons, as I noted, are not even really cons for most people, as they are issues of preference, but I thought it was better to be as thorough as possible.