It seems really lightweight: the UI is spartan but snappy, loading a file is instantaneous, etc. Downloading and installing a plugin is as easy as dropping a Lua file into a directory. And even after installing several plugins, the speed doesn't seem affected.
On the other hand, it comes with hardly any feature out of the box, and everything must be covered by plugins. The plugins are really "atomic". For example, one is to auto-indent, another one to auto-format a block; one is to highlight the matching bracket a second one to jump to the matching bracket, and a third one to automatically insert the closing bracket, while yet another one draws rulers to visualize the block between matching brackets. Do you want to set markers and jump between then? another plugin. Build from within the editor? another plugin. And so on...
The plugin "store" looks good, but accessing it from inside the editor is a poor experience: sometimes it just hungs and you have to restart the editor. Additionally the fact that plugins, themes and fonts are all mixed up doesn't make it easy to find what you're looking for.
Final judgement: if I need to select and install 10 to 15 plugins just to make it on par with a stock Vim, I'll stay with the latter.