I prefer minifyx as you can directly load in scss files and it handle the compression of them.
In light of HTTP/2 this is an interesting discussion to revisit because if you are serving your site over HTTP/2 the best optimization can be to do nothing. That's right, stop worrying about counting HTTP requests and concatenating files and let HTTP/2 do its magic.
If you are looking for an easy win performance wise: GZIP. Enabling GZIP will have more of an impact than minifying files ever will.
To support HTTP/2 you need to
- serve your site over HTTPS (even though this isn't required in the spec all browsers require HTTPS)
- your server needs to support HTTP/2
- your user needs to be in a modern browser or the handshake will fail and they will get HTTP/1
If you do use server side minification practices you may want to use getCache and/or statcache to cache flat to the filesystem for performance.