In reply to Taylor.

My Main question is if you are running WordPress with tens or hundreds of thousands of records, what hardware are you needing to throw at it to manage that? I'm guessing at high-traffic to keep responses lean you are needing to cache and use some ingenuity, and it's not just Core WordPress doing heavy lifting.

The main reason people rag on WP, is that some of it's core structures, such as EAV. They don't scale, it's not a WordPress thing, it's a mixture of database system internals and basic compute performance. Look at Magento, it's wonderfully complex, but without the 2.0 refresh and a lot of caching, it eats server resources. If generic structures could perform incredibly well, nobody would take the time to invent complex specialised objects.

While I don't doubt WP can likely handle hundreds of thousands of posts, all with ~50 meta fields. I know it will crawl doing so for reporting, and other features that will become necesarry as a site grows. I say this without conducting any testing; not because I'm mad, but because such large result sets and queries will inevitably lead to the DB doing more thinking than it should. I'm a little concerned to see so much ignorance of the fact that to do more (including casts for some WP meta logic), will always take time and require rewrites and change-in-approach to problems.