The only thing I wish I'd knew about the first host I've used, would be to know that they'd sell within a couple of years after I signed up with them.
But that's a thing that one can never predict, and I don't blame them, given that they've built a great Company and received an offer that was, apparently, too attractive to pass on.
I'd second to always look into the fine print and renewal / upgrade conditions, to avoid having to switch hosts once the full pricing goes into effect and the experience doesn't match.
Many hosting offers act as a "loss leader" as they sell the first Year or so below what the actual cost is, only to get the client hooked on an auto-renewing contract.
If a host is focused solely on getting as many clients as possible on these too good to be true sounding type of deals, they're way more likely to oversell their service, which more often than not leads to tech and performance issues, with less dedicated and less timely support.
All and all, I'd not hesitate to pay a little bit more, if I can be confident about what I get, and that it's a host that I can rely on and work with for years to come.