Anyway, as a wakeup call -- if you have a business critical domain name, you need to find (and use) a registrar that has a registry lock procedure for the TLD you're in. A registry lock means the registry won't process changes from your registrar unless you authorize them, which makes it a lot harder to change things on purpose, or by an attacker. I imagine abuse takedowns could still go through though -- but there will at least be more people who know you care about your domain.
If your domains are riding on a credit card, you potentially have a failure mode of "card was declined, my domain did not renew, everything is down."
A commonly recommend option here in HN was NameCheap. Earlier this year without any notice they modified our DNS servers completely taking down our SaaS product.
Why? Some migration script run incorrectly.
They offered me a random TLD for free for one year as compensation! I declined.
I would not say MarkMonitor is a tool for startups. It's a tool for organizations that would lose a lot if they lost a domain. I bet Zoho wishes they could go back in time and spend $10k to avoid this problem they had.
In my experience, the opposite is true in both cases. Big registrars can’t afford any support costs since they prefer to squeeze the price down as far as possible, and therefore they prefer to simply lose or outright drop any customer in case of any and all problems. Conversely, small registrars may charge more, but have better (i.e. actually existing, and sometimes even dedicated and personal) support for when things go wrong, and have a vested interest in keeping you as a customer.