I have the standard 18650 Legacy with extension and kick,and i love it.I stopped using my Smok Telescope when i recieved it.it is very simple to use,just need to clean contacts once a month,standard maintenance.That's basically it for that one.
The Curve that was just released by Nhaler is also a very sleek and awesome mech.On the nhaler thread 2 people have recieved theres already with pics and they love them,of course they are nhaler fans too,but whatever works for you right.Either or both would be a good choice and easy to use also.
EDIT: With the Legacy,if you are not using a kick which has protection,i recommend getting the Holocron ShortStop Fuse.I use it when i am not using the kick and it adds the protection you need.It is also reusable unlike the 2 cent fuse,which has to be thrown away once it trips.