As a first-time solo developer, I've been debating the pros and cons of demos as well. People can only get so excited by screenshots and videos. While an early demo may turn some off with bugs and missing features, quality feedback could be invaluable. If a potential player dislikes an aspect of gameplay, it'd be better to know about it in pre-alpha than learn about it farther along in the development cycle. Easier to fix.
Viewing post in (R.ECC) - Are Pre-Alpha demos worth it?
That is absolutely TRUE. I've always been a big fan of demos - but at what state are external demos considered viable? Pre-alpha, Post-alpha, Early beta or late beta stages? Because we can lose some genuine market interest if we publicly show something before it's ready to be seen. I believe we as indie devs many times suffer from the "To show or not to show - or when the hell to show" syndrome, as 90% of the time our games are in an unpresentable state.