He never tried anything else.
For speed, vi is number one, followed by sublimetext.
Vim feels sluggish compared to NeoVim.
NeoVim feels sluggish compared to Helix.
Of course, if you offer only a portion of NeoVim's features the speed improvement should not be surprising.
Anyway, can you name a few NeoVim features you miss in Helix? I still use NeoVim now and then, so I'd be happy to learn more, even if it's something small.
This is one area where NeoVim afaik comes out on top: Vimscript isn't fast, and NeoVim allows Lua plugins via the embedded LuaJit, and those should be significantly faster.