Ok if you're bootstrap it probably doesn't make sense but otherwise fivetran is fantastic for not having to deal with a boatload of third parties constant API updates and changes. If your core competency is something else entirely and not doing ETL, then it's worth paying for so you're not wasting time on doing that ETL work.
Yes, I've used Fivetran at VC funded startups that I worked at and I understand the value of not having to build this piece of common infrastructure. Although we did experience regular (probably once every couple of months) issues with our ETL getting out of sync. We even had to do a full re-sync on a couple of occasions (which to their credit they did for no charge).
As I said, I totally understand this market and why these companies are valuable. I respect the work they do. But while I am a tiny, tiny startup I don't want to lock in to anything and I know I can handle the amount of data myself with little effort if I have a basic open source alternative I can manage myself.
