I got a 510 last week (as a followup to my first pv - a 901)
It did take 2 days for the atty to break in fully and start producing some nice vapour. I use it about equally with my 901. I tend to get slightly less vapour (still plenty) out of the 901 and more flavour.
Draw technique takes some time to get used to. I tell people:
"Use 30-50% of the suction pressure you would on an analog, and draw for 2-3 times as long."
See what kind of hit you get then. Also as someone mentioned, nicotine content does affect throat hit (as a positive correlation)
Enjoy!