The processing overhead is pretty minimal (take a look at our iMX6ULL, for example), because the containers are just fancy processes at the end of the day. The only real drawback we see is boot time, but you can optimise that as well.
container could be really heavy to me, as it shares nothing with the host(other than the kernel some volume mounting), lxc seems much light-weight to me as it shares the host libraries and packages.