I started out with a 2-piece GreenSmoke, hated it, and soon went for the 510. I specifically chose it as it is the most hands-on model, with user control over everything from DIY juices to cart
mods to eventual batt
mods, although I have not gone that route yet. It is finicky, but for me well worth the effort. I don't have flavor issues at all, and I use VG juices only, but a little vodka to thin the thick
juice is required and brings flavor out a lot.
Initially I would pick a model that has a lot of info about it here. Certainly the 510 is that, and so are several 2-piece systems, like the kr8. Just jump in and learn as you go! No model is perfect, and they all have a learning curve. Have fun! Vape on!