Just want to chime in. I think that people are very confused on this topic. Think more in terms of
Exploit Success Rate - what is the rate of kp versus successful exploitation yes it is true 5.05 is pretty good about this but it will have occasional kp. I would rate 7.02 just below 5.05 as it has ok success rate not so much kp. I would rate 6.72 just below 7.02 due to more kp from my observations but it has a higher success rate oddly and I would rate 7.55 as the one with the lowest success rate most kp.
Compatibility No contest. 7.55 wins hands down. Which is logical. When I talk about compatibility I mean can i install the true not backported fpkg and does it work? Does dlc work? Do the latest updates work? Obviously this compatibility will go down as you go down in firmware. To me this is important since I love dlc and updates are crucial. You do not want to spend all this time creating a collection of fpkg only to play them and deal with buggy games. I found in my testing in some cases the backports were breaking hdr features of games. I noticed no one else report this. Keep in mind. Many don't actually play the games. Now of this group many don't use hdr. So it's hard to get good information about this.
Stability - I would describe stability as I can play for hours and not crash in the middle of the game. I can use things like FTP or Media apps and not crash. I can use things like Linux or homebrew and again not crash. So the true concept of stability is being misunderstood in this scene. People are confusing stability with exploit success rate and those are just plain 2 different things. With that said I have noticed random crashes on all firmwares since 4.05. In the early days of 6.72 this was quite bad. Simply ejecting a game disc could cause a crash. Simply switching a usb device could cause a crash. This is unacceptable. 6.72 is much more "stable" since those days. At this point in terms of PS4 Dash stability I would rate 6.72 pretty high. Same with 7.02 and 7.55. In terms of Linux usage I would have to say I noticed an odd difference when I went from 6.72 to 7.55. The linux boot rate is poorer and instead of me smoothly booting into linux I have to do an hdmi unplug replug. So in terms of linux I would say 6.72 is best. When I tested linux on 5.05 I had tremendous issues on a pro. Not sure why. Maybe old payloads. On a phat worked great in terms of booting. But since Linux is best used on a pro I would have to give the nod to 6.72 for best stability for linux. Similar to HDR this is something most users are not discussing.
Another way one can view your question is what is best host? To me after pretty extensive testing I would have to say night king. Al azif performed poorly on 7.55. I test Karo extensively. Performed slightly worse than night king though not immediately apparent which can cause what I would call a placebo effect. You think it works well but as I tested it had issues with rest mode and exploit success. There are many other menus I tested quite a bit. Some of it was recorded. But I would say no reason to address them.
I possess the number one headband on ps4 scene:
I would love for one day one of you to wrest it from me. But I have many hours in the simulator. I just don't see it happening until I die. Though as anyone at the top of the mountain I welcome a challenge.
As the #1 I beseech you all to share your thoughts knowledge and information. Just as I have. Don't be afraid of change. We must explore. We must test. We must communicate. Together we can make this scene better. All knowledge I attain I share with the scene.