Again, these aren't the documents that YC and TS use for their admitted companies; these are the docs for the round after that. These are actually more useful than the internal YC/TS documents, since you can use these documents for your discussions with angel investors outside of a YC/TS program.
Again, I prefer the Techstars documents because they're more similar to standard Series A/B/C VC documents that I saw in my prior life as a lowly VC Analyst (still bitter I didn't negotiate the Associate title). But thanks to both Y Combinator and Techstars for releasing this stuff. They're both much, much better than the model NVCA documents for a potential angel round. You can't go wrong with either.
