Summary: (1) He's a better programmer now, having internalized RoR best practices, and can apply it to raw PHP code, (2) Decreased load issues, (3) All company code can be PHP, and it sounds like there was a lot of legacy code that didn't play well with Rails portion.
Would have been nice to read more about the mismatch points between Rails and legacy code. Was this a legacy DB structure that couldn't be loosely coupled to the Rails side, e.g., exposed as an internal REST service?
I also wonder if others can just as easily extend his code than if he had used a well-documented framework like Rails. In any case, it's impressive he rewrote the whole system (doesn't look like a small web app) in 2 months.
I haven't been on news.YC very long, so maybe that was mentioned as an issue a while ago. When Rails first came out, there was a paucity of documentation. The book "Agile Web Development" came out to meet the need. Now when I go into a bookstore or search through Amazon, I'm shocked by the number of books on Rails and Ruby. Truly amazing. Then there are the self-published outlets like peepcode.com, flexiblerails.com, etc. Rails and Ruby coders are also active bloggers and IRCers. The folks at Caboo.se, in particular, have been working on internals documentation. (http://www.caboo.se/documentation)
In the rails API docs (api.rubyonrails.org) next to each function you can click 'show source' to see what's going on under the hood. I hardly have to do this.
But when I do, it's usually just 5-20 lines of code that's not that complex to grok. (but you're right, not many comments inline) It would not be fun to try and decipher RoR internals as a new ruby programmer.
There's also the caboose edge API documentation. It's updated 3x per day from the most recent rails edge code and has all the private (#:nodoc) methods exposed:
Would have been nice to read more about the mismatch points between Rails and legacy code. Was this a legacy DB structure that couldn't be loosely coupled to the Rails side, e.g., exposed as an internal REST service?
I also wonder if others can just as easily extend his code than if he had used a well-documented framework like Rails. In any case, it's impressive he rewrote the whole system (doesn't look like a small web app) in 2 months.