I too myself was looking for a strong hitting e-cig. I wanted a lot of smoke/vapor and I nice Throat hit (Throat hit is the feeling you get in the back of your throat just like when in inhale a real cig)
I looked over a bunch of different branks, the fifty-one, the screwdirver, the blu e-cig, joy510, Janty stick. I looked at a lot.
After a lot of research I had narrowed it down to a janty stick or a joye510, I liked the Janty stick because it had a very long lasting batt life, however the odd shape of it wasnt my style beacuse i wanted to be able to hold it like a real cig.
Then I came to the joye510, with a manual switch.(Ill get to what an auto v.s manual switch is in a little) Let me tell you, this thing seems like a MONSTER, it has great vapor production, and from what I hear a great throat hit.
I purchased mine on e-smokeytreats.com as a package, I got the 510 starter kit, witch in reality comes with enough extras to have 2, yes 2 working e-cigs. you get a spare batt and a spare atomizer. plus you also get 25 cartrages of different flavore nic. on top of the starter kit i ordered a PCC, which i believe stands for a Personal Charging Case. which means this case holds extra cartrages in it, plus you can plug your batt into it and the pcc will charge it, the PCC is like a batt pack on the go, you charge the pcc at night, and then unplug it and take it with you during the day, and you can rotate your batts and it will charge them while your out.
Anyway, So i got the 510 starter kit, a PCC, and some extra e-liqued. It came out to 110 bux. and I think its worth it.
I personally have not tried it yet, ITS SUPOSE TO COME TOMARROW!!!! WOOHOOO but I think I really have done my research and I will be happy with my purchase.
Anyway... as far as the "BUTTON" on the 510. what that is, is a manual switch to turn on the atomizer.
Automatic switches work like this, when you suck through the e-cig, the air pressure ativates a switch that is built inside of the e-cig. The downside to that is when you hit the e-cig too hard, or too long it will turn the e-cig on in a sense and you have to wait till you can hit it again.
A manual switch is, well manual. you press the button and that activates the atomizer, and you can suck, and suck, and suck, and suck, until you melt the damn thing, and get as big of a hit as you want.
The downside to that is that you can fry your atomizer, and or melt your cartrages. so just use common sense, dont do a sucking marathon on it and you should be fine. (if your in the mood for some deep sucking, i segest you talk to your wife/gf, but leave the e-cig out of it haha)
All in all, your best bet I think would be to go to e-smokeytreats.com and order the 510 with a pcc, and if you want, get some extra nic juice from them, or whatever site you want.
Best of luck to you.
-Derek