The thing I always disliked about internal battery mods, is that when the battery would go bad and wouldn't charge anymore, I would have to throw the whole mod away (what a waste). I have always bought devices that took separate batteries (and bought a good charger), that way when a battery goes bad, I would only have to replace the battery. Having both is OK I guess, some like it, but I think you want to know which one to get, as you can only get one of them. I have the P80 and love it, it is small, light weight, and compact. The FJ200 goes up to 200 watts yes, but how much power do you really need to vape with, if above 60 watts or so then the FJ might be a better choice for you. You can charge the P80 with the battery in it though, but get a external battery charger as soon as you can afford it and use that to charge batteries with (like DancingHeretic said).
Your post is alright Heretic, I don't think it is harsh at all.