2015 nissan home L2 chargers

I have leased my car 2015 S model with QC and I am looking into home chargers. I'm looking at the openevse and the Juice Box.
Is their any big difference in either? Does one charger faster using less electricity? I'm looking to urchase a unit that i can also take with me also so i can possible use it at camp grounds. I think this is able to charge at the 6.6 also
I'm thinking of picking up on of Glens open eves. would i notice much difference between the the 24 or 30 model?
Thanks for any info or input

you've come to the right place - search EVSE and you will find a cornucopia of information here.

No difference in charging speed. They will be limited by the Leaf being able to take in the power at either 3.3kw for the S trim, or 6.6 kW for SV and SL.

Both EVSEs have the same basic efficiency.

In general, 120V EVSE is ~75% efficient, from power mains to battery.
In general, 240V EVSE is ~85% efficient, from power mains to battery.

This may be oversimplified, but the EVSE itself is really just a smart relay. When it detects that a car is there and that the car is ready for power, it closes the relay.

So any brand EVSE will do the same thing, Juicebox, OpenEVSE, or commercial.

Bob