HI Heather
Welcome to Coda - you have found the motherlode… 
Next week Coda is having a “Block Party” where they will be making some long anticipated announcements.
This thread is VERY old, so most if not all of the topics mentioned in 2019 has been addressed. We will always want more performance, of course, but it is quite fast at the moment.
I am fairly “all in”, having moved here from Notion, which I have stopped using. I have also stopped using Roam Research. My two big documents are one for work, which incorporates a task list grouped into “gaps” that need to be developed for a software project. The task list, using indicators, also doubles as an issue list. The “gaps” are stored in a table, with their metadata, and links to a page per gap, Notion style, where meeting, design and other notes are made. I also have a “dictionary table” where I define terms used in the company. Using @, anywhere I used that word or term in the doc, I create a hotlink to the definition of the term.
For my personal use, I have something very similar, but the “gaps” are interesting info to be further researched, or mini-projects that I am working on.
I have also stopped using my QuickBooks, and built something to analyse my bank accounts in Coda. (I am NOT building an accounting package, just a tool to analyse my monthly income and expenses.)
So task management, yes; project management, yes; Wikipedia like functionality, yes. But remember, you start with a blank canvas, or hopefully with a template you found in the gallery. But what you do with it is up to your imagination.
Regards
Piet