What do you use for video editing?

I made a quick vlog post to ask your thoughts on Video Editing software.  I’ve had a channel on YouTube for a little while now and I’m curious if it’s time to invest in better software…or if I’m in a good place with what I have.  I use iMovie for pretty much everything, but my goal is to start taking better quality video (using a video camera rather than my phone, desktop, etc.).  That also brings me to my second question, should I consider upgrading to an external microphone?  Wanted to get your thoughts and see what opinions and/or experiences you might have.  Let me know what you think in the comments below.  Thanks!