if she is anything like me, there is no way i would have gotten a vv mod/box mod etc etc. for new vapers, its a learning curve and adapting to what you have, moving along slowly at a pace that feels natural. true, most often they end up getting the mods and bottom feeders and there are plenty who just cant/wont deal with the size and looks factor because it doesnt appeal to them.
that being said, going to an ego from a 510 is a very natural step (i did the same).
sounds like you are always used to cartomizers (510 threading) so you can use them all on the ego battery.
the 510 lasted me 3 hours before the battery died, the ego lasts me about 8 hours.
if you like the 510 you have, you will absolutely love the ego.
however...if i was you, i would go with the riva (same looks, same everything as the ego,'cept the voltage is just a tad higer off the charger), because they are also less in price.
this place has good prices:
Electronic Cigarette - Starter Kits - Riva 510