The issue with this question is that most of us, only know the lift we are running. So the answer would be the one we run. The other issue is that after spending 2k or so on a lift no one is going to want to admit they got burned so they as a general human nature standard won't say the one they bought sucks.
I have been wheeling for over 3 decades. I have had many lifted vehicles. As a "general rule" once you modify a vehicle for a specific purpose you loose some of the use in another area. The more specific you go the more you loose elsewhere. The extremes for this is a rock crawler would generally make for a horrible high speed desert racer. A mud truck would probably be a horrible rock crawler. And almost all of the above sacrifice streetability.
Having said that, I really am impressed with my Nth lift. I have never had a lift "kit" improve the on road handling as much as Jim accomplished with some modification to the factory geometry. This to me is a true testiment to Jim's engineering skills and his ability to actually improve the ride.
The problem with the whole Nth kit thing is that they have been bought up by AEV and we don't know when they will release the JK lift kits and if it will remain as much of a Jim Frens design.
However my kit was a prototype with the goal of taking it out and beating the poop out of it and to try to break things or have parts fail. I accomplished this mission but now since Nth no longer exists have some very trail tested parts that need replacing. I can no longer go to Nth for the parts so I also have been shopping around.
I settled on Poly Performance
for my source for replacement parts and will be running their products in my ultimately mostly Poly Performance
hybrid lift kit. My reasoning was that of appearance of durability and usability. I will use my JK and sometimes hard. I want stuff that is truly "Trail Tested" and isn't going to break or complain about the trails I have chosen.
This isn't to rule out other companies. I also considered Rock Krawler
and in talking with them they have some interesting plans coming up an a fairly radical departure from what currently exists for JK lifts. I also considered Rancho
and Rubicon Express
I am only familiar with one other name brand of lift kit that isn't mentioned above. And my decision to not even consider them was based more on a personal level than an engineering one.
This isn't the complete list of what is out there and this doesn't indicate that those not mentioned (save one) is a lift I would not consider. I just don't have any experience with them.
I would say that when purchasing a kit, I would put less value in what people say about their kit, as much as how much they don't say and primarily on those that have had to deal with the customer service side of a companies business. If a company dos not stand behind their product, I wouldn't even bother with them.
When considering a lift kit also put into your calculations that the lift you chose will be the one you are putting yourself and your families and friends lives on. What you are changing out and hopefully upgrading is the suspension which is the heart and soul of the performance and handling of your vehicle. How safe you will be on the road is determined by your vehicles performance and handling abilities. I would say that my experience with my Nth lift has demonstrated that proper engineering can do wonders to the performance and handling of a vehicle. I'd put my money on the engineering over someone that doesn't have engineers and has simply put on taller springs and longer shocks.
I hope this helps or at least gives you some criteria to consider when considering the lifts available for the JK's.