Ask HN: Is it worth starting a SaaS in a niche that already has a clear leader?

I've been wanting to make a SaaS business for years. I've done PHP freelancing for years for some cash on the side of my full time Systems Engineer job, but rather than develop stuff for other people I'd like to take a break from that and make something for me. My work, and several of my clients I've had, pay for and use StatusPage.io. I've always thought I could make something similar (obviously not as fully-fledged as SP.io) as it would interest me. At work I play with stuff like Redis, Galera clustering, VM management (Puppet etc) and outside of work I play with PHP - so this seems like it'd be a good project to bring them both together - I get to build/develop a site and also make it autoscale with AWS (never used AWS) etc - fun all around. Is it worth doing months of research trying to find an 'untapped' niche or something that doesn't have a major leader, or is every niche going to have competition and I should just give it a go r