There's quite a bit more than a bit less battery life on the 510. I get an hour and a half out of a 510 battery. I get 8 out of an eGo.
And if you're ok sacrificing that for a slimmer form factor, go for it, but make sure you have extras. For me, a 510 battery *barely* charges fast enough to finish by the time I kill the next one. But I vape fairly heavily, so your mileage may vary.
In terms of what advantages atomizers have, well, some of it is subjective. Some find they taste better than cartomizers. Others think cartomizers taste better. I like both.
Atomizers give more vapor than cartomizers. Pretty much everyone agrees on that. I seem to be able to get a lot more vapor out of my cartomizers than most, but atomizers still usually give more.
Cartomizers tend to give me more throat hit. Again, there is some disagreement on this, but I think a lot of people find that.
Cartomizers *generally and in my experience* don't last as long as atomizers. But this is also subjective. Most people get 6 or 7 uses out of a carto before it tastes weird. Some people wash them and have great results at getting them to last longer. But I never did. For me, 6 or 7 refills was it, because they never came out performing well after a wash. That was just my luck with it. It's also a lot of trouble to go to.
Atomizers last a lot longer for me. I have some that are nearly 4 months old and still kickin' out the vapor, with regular cleaning (which is less work and time than with cartomizers). But, others have less luck. Some people can only get them to last a couple weeks no matter what they do.
Cartomizers are much less expensive than atomizers, but if a carto is only lasting me 6 or 7 refills, and atties are lasting for months, it's cheaper for me to get atomizers.
If your luck is different, that may change the cost/benefit for you.
My advice? Try both.
If you get a Kr808, get a 901 atomizer as well. They will work on your Kr808 batteries with no need for an adapter.
If you get a 510 or an eGo, get some 510 cartomizers.
Weirdly, the luck people have with them does seem to be really individual and there's no hard rules about it.
