Starting this thread as I submitted my application this morning!
I've been a LPR for 12 years but I was so unexcited about the idea of dealing with the USCIS again that I hadn't filed until now. Then time came to renew my green card and I thought, oh well, I might as well file my N-400 instead. What eventually convinced me is that citizenship applications are apparently processed much faster than I-90s! I'm the anxious kind and traveling around with an expired card and a piece of paper didn't sound great to me. Anyways, the online application was shockingly fast and easy. Now the waiting begins!