I have only one mod so far and it is the iStick 30w. It's a great little mod and does what it is supposed to do.
I think it's the best first mod for everyone. I am
waiting for the EGO One Mega v2 I ordered last week.
Excited 
For trying TC, I'm
gonna buy iStick power because it's cheap and goes way up in wattage and it
handles stainless steel which the
iStick 40w does not.
I'm
not gonna buy the removable battery ones because I don't want to deal with all the safety precautions.
Imagine if you had to change batteries on your phone every day and charge them separately from the phone