Rebinding C-b to C-a is a necessity for those of us whose muscle memory formed on GNU screen, been doing this for years. I like to set status-right to include host load average, with something akin to:

set -g status-right '#[fg=colour39, bg=colour234]#[fg=colour160] #h #[fg=colour088]avg: #(cat /proc/loadavg|cut -d" " -f1-3) '