Excited and happy to see such a project!
I am using iTerm2 on a maxed-out MBP 15 Retina quad core and Xshell on a $150 Asus Cherry Trail netbook. You won't believe it but Xshell on the crappy netbook feels light-years faster and more responsive than iTerm2 on the MBP.
Wondering how Alacritty will perform, looking forward.