I heard many times "well something like this happened at XYZ company and this is what we did and it didn't or (or did work". Granted many problems are new with each venture, they all had a vast set of knowledge and startup experiences between them. I learned a lot by working with them and hearing their reasoning behind decisions.
Their network was also very, very strong as a result of having been around the block. This made for easy access to almost any company we needed to speak with.
It is also neat (and I learned the most) to be able to communicate on a very high level in all discussions. It was a totally different experience from the prior startup where I had to preface everything with a breakdown of the basics first (this is what SEO is and how it words).
By the time I joined mine, the founders left - I don't presume the reasons, but the company is currently headed by a CEO with a passion in the space and the founders as advisors & board members. The company feels like any other startup I've been at, high pressure with products that at one point were dangerously close to failing without some herculean efforts to reverse technical debt, create a pathway to scalability, and timely releases of new products/features despite waterfall planning.
I have found that engineering gets the shaft, just like at most other companies. True leadership is appallingly missing, and heedlessly put companies at risk...but I digress.
It was really different from working for "normal" first timers. He was much faster, more responsive and more likely to understand things like scope creep and technical challenges encountered ("more common sense" might describe it).
It was a real pleasure. I'll probably offer a discount to serial founders going forward...
NB: it might not mean the company "doesn't have funding issues". This founder (and many others I know) took external money because it makes sense financially. Park your savings in real estate and stocks, and take the much better terms investors will give you because of your track record. He was also quite careful with it.