I am both a 901 user and a V4L user.
I like my 901 the whistle tip makes it really nice. But it lacks ease of use. I have to make up my carts.
For my supplies I have
A funnel
a needled syringe
Stuffing- wicking
nicotine liquid
Alcohol
baby jars
2 batteries
3 different chargers
I pouch to carry my e liquid extra carts, stuffing, attys, battery, the needle.
Since there is not a good way to cap the carts I have to fill them as I need them. I can't just pop one on and be good to go.
Now its good vapin and flavor is so so. But I have to replace carts often or top off or drip.
With the Vaporking. I wont need to carry anything with me but my carts. They are VERY easy to refill. No fus no soaking over night no pre cleaning.
I pop one on and I use it. I don't have to worry about carrying
juice with me or extra carts, stuffing etc.
One cart does last me all day. Infact I'm still using the one I got yesterday.
But I'm not a major vapor yet. I'm still working on getting it down. Cart usage no matter what is dependent per person. Some last 3-4 hours. Some go through 2 a day. It is just different.
The 510 I hear is great to. But the only way your truly going to find you nitch is to try a few models. I tried the 901. Decided there was way to much involved. And the carts work for me. I can refill them with ease. I don't need anything but a bottle of
juice cart and something to pop the seal off.
Again start off with something you think you will like. Everyone is different. And I can't tell you what you should or shouldn't try. I'll only offer my advice. And my experience.
Don't let others bother you by bashing a product because they don't like it, or have never tried it. That product might be the right one for you.