Any of the ones that
@Paratech mentioned would be a fine first.
Personally as my blog indicates, I wouldn't advise a new vapor to start with a Mech, like the two you mentioned.
I would get something more in the regulated world, like the suggestions made. learn the basics and get to know the gear in general, then go ahead and get a Mech if you want. a lot of us started with them, because the regulated gear was not where it is now. If you did want a single battery mod, the Pico provides ample power for most tanks on the market; if you were looking for power, the pioneer4you that paratech mentioned would be my first choice; because, of its chipset.
If your heart is set on the mech, I'm partial to the stingray x over the smpl. I have both authentics and the button on the stingray is more me, plus you can use the 510 top, if you have an Atty that won't work as a hybrid.