The above would work well for slightly heavy and heavy wettings, but for VERY heavy wetting, the only diaper I can currently recommend is Rearz Safari or one if its variants like Princess. Paws and Space are very good, but last night my body played catch-up with hydration and I wet heavily (floods) maybe five times overnight, and my Space was a few inches from the back top by morning, close to capacity and no longer able to hold a full wetting at a time without leaking. Certainly not floodable again. So I actually got up in the morning with a fairly full bladder. (unusual for me) Owell at least I didn't have to get up and change overnight. It's rare for me to need that level of capacity, but a bit unpredictable. I have safari on-hand but just had gone with a space, which for me normally would be a totally safe bet for all-night protection.
I'd suggest giving Space a long test and see if they are reliable for you - they probably are, and are significantly less expensive than safari. Space should be sufficient for 95% of diaper wearers.
oh also if you don't need really high capacity and are just looking for better capacity than cheap stuff, there's a lot of good options available. any of the bambino line, abena xplus, molicare, mydiaper, tykables, dc amore, and many more, the list of mid-to-high capacity diapers is actually quite long and offers a great variety of design.
I can't say for side sleeping, because I've always spent the night sleeping flat on my back from a very young age(likely the tendency to leak side sleeping is a factor there) but my most reliable night diaper that is exceedingly rare for me to leak in(usually only when I've been drinking or there's a diuretic like Milk or a shot or medicine or something, and even then it'll usually handle it) is an Abena AbriForm L4 with a Maxi AbriLet Booster in it. It's what I sleep in every night.
I think it ultimately depends on which country your in and what suppliers of diapers are available at that time because some are better than others a example of this is the Philippines most diapers here are rubbish in terms of quality but others are good so its worth doing your research before buying any diapers remember that the best are often the most expensive to buy and whilst I can't speak for diapers in the U.S. and Canada because I don't live there I do understand why most of the best diapers are in that country.
In the UK where I live the best one I have come across was either Abena Delta Form L3 or Tena Slip Ultima I personally prefer disposable diapers because they are more convenient to wear than fabric or reusable ones although again I understand why people might prefer more environmentally friendly diapers but in my case its more because I am allergic to certain fabrics and just because they are billed as being more environmentally friendly they aren't in reality because they need more energy and resources in the form of electricity and water.