Might as well just go buy an Infinity Pro or Buzz Pro
Seriously, what you asked about is an entirely reasonable product from a decent company. It is perfectly fine for starting out, seeing how vaping works for you, and some people stay with KR808D-1 long term -- they like it, it works for them, which is what matters. Matter of fact, I keep a couple of KR808D-1 batteries, for times when I want a small auto battery, need to be hands-free or discrete.
The above being said, the KR808D-1 batteries are smaller than, say, an eGo/Riva, which translates to shorter run time between recharges. If you are interested/willing to use a manual battery right off (one where you press a button to provide power, rather than just inhaling), and are a heavier smoker, then the extended run time between battery changes may be a plus for you. On the other hand, carrying a couple of KR808D-1 batteries (Mega or XL are longer run time, more mAh) shouldn't break anyone's back.
As to cartos (the combined cartridge/atomizer, vs. separate pieces), KR808D-1 has a quite good selection -- 808 has been "doing" cartos as their main liquid delivery method all along. There is a very good selection of cartomizers, including many prefilled, which simplifies things for some -- just screw the carto on the battery and inhale. Longer term, going with blank cartomizers is more economical, and provides you with access to a wider selection of eliquid, but for starting out a kit with some prefilled cartomizers in different strengths and flavors is a nice way to go. 808 doesn't have as many variants popping up as the 510 crowd now, but a fair amount of that is undoubtedly due to lower voltage 510 users chasing the warmth and vapor production that 808 has always had (classic 510, eGo, and earlier Riva units all ran down at 3.2 - 3.4V, vs. 808 running at 3.7 - 3.8V; power, which directly relates to warmth and vapor production, is related to voltage squared).
I touched on auto batteries earlier. Haven't seen it yet, but this thread is about due for the "you must buy manual batteries" comment. That's not necessary, unless you absolutely want to use an atomizer system and drip. Overall, manual batteries might be a bit better for longevity, but we aren't talking the price of a car here. If you are happy using cartomizers (I still do, exclusively), blow through them onto tissue prior to putting on the battery (to clear excess liquid), they run fine, and are absolutely necessary if you want to use them when you cannot press the button on a manual (when I have a chainsaw out, or the lawnmower, I want to be able to vape, similar to when I used to be able to smoke while doing these activities -- I can do that with an auto 808 battery, not with a manual).
Good luck -- a lot of good choices out there, wish I had found ECF before buying my first personal vaporizer
