It really depends on what you want to do, what you feel is missing from your vape, and how technically versed you are.
Personally, if this is your first dive into rebuildables, and you want to buy something that will always be 'ole reliable', then a kayfun and the provari is for you. Provape has been around for a long time, and their product is reliable and an excellent staple. Even if you venture out to broader and different things, the provari / kayfun combo will always be a solidly legit combo. Don't just take my word for it, Phill Basardo the widely known you tube reviewer has said multiple times that if he had to choose only one setup to use forever for vapeing, he would have a provari / kayfun combo. It will give you decent flavor, reliability, and clouds. Keep in mind that there is a new version of the provari in the horizon.nit will probably be out in the next few months. The rumors are that this is going to add some more features and flexibility to the units that make others think of the provari as 'outdated'.
If you want to chase clouds, or buy a bunch of different attys to experiment with builds you see rip trippers do, then getting a DNA 30 is going to give you some more options and flexibility. I'm not saying these things are 'bad' per say, but you can start out slowly with a 'typical' ~1.0 ohm coil on a kayfun on a DNA 30 and be completely satisfied, and then one day say... Hummm... I want to try that bad ass looking coil build on a new dripping atomizer I saw on you tube that comes out to .5 ohms. You can do that with a DNA and probably be much more satisfied than you would with the CURRENT provari.
If you want to do SERIOUS cloud chasing and win cloud contests, then a DNA is a good starting point, but you are going to be limited quickly as you delve into super low sub ohm builds in the .2 or lower range. You won't have near the capabilities a mech mod with a dripping atty is going to allow you to do.
Hope this helps.
