I can't say (and no one really can) that the 510 is the
best there is because there are so many models out there. It's not much different than a car or truck. I drive a Dodge Ram 2500 4x4 with a Hemi and there'll be dozens of Ford and Chevy guys telling me that their truck is so much better than mine - it's all a matter of both personal preference and personal experience.
I started out 2 months ago with a KR808D-1, a 2-piece PV which worked well enough that I quit smoking analogs
instantly after 36+ years of smoking. A week later and after reading, reading and reading some more on the forum here at ECF, I made an informed decision and purchased my Joye 510 from Cignot and have not been happier. Do I
like it better than my original KR? Absolutely, because I can do more with it as far as refilling my own carts and there are mods I can do and so on. Is it
better than my original KR, not a whole lot because it worked well for me when I first started and I wouldn't hesitate to use it again if I wanted to.
You have to do your research. Grab a cold beverage of your choice and spend some hours on here reading and searching and reading... You'll pretty much find all the answers you're looking for just as I did and make yourself an informed decision on what to buy or do next.
As far as everyone coughing when they vape their 510 on videos, not all of them do, but I noticed that too. Primarily the person vaping is demonstrating the capabilities of the 510, how much vapor they can make, and with a strong e-juice they are getting one heck of a throat hit which will make even the most seasoned vapers cough, so don't be misled thinking that a 510 is bad because it makes people cough. It's not much different than most PV's available.
Oh, and as far as the 510 batteries being "bad", they're not bad - they just don't last very long. I usually go through 3 fully charged batteries a day. If you consider their size which is very small, they just aren't large enough to hold a larger charge. But here comes a mod like the Nicostick (do a search on that one) and voila - perhaps a full day or more on one charge.
Off my soapbox... again...