For me, there were some questions about my technology, but not a lot. Mostly we agreed on terms, and then they came up with a 40 page contract :) (the bus-dev guy said they don't really treat a small acquisition like mine that much differently than a larger acquisition in terms of contract verbiage). I had my lawyers (no I did not have any before this offer), review it.
But overall I felt that someone, who later I'm pretty sure turned out to be the CEO, had told their Business Development guy, just acquire this thing (and bring him along if you can), so they just went about doing that and it came out ok.
Note that it's pretty common for years to pass between the first and second stages of this process, and there are any number of reasons why acquisition negotiations can either suddenly accelerate (it becomes competitive, partnering isn't going to work as a fallback, the target is going out of business, the acquiring company needs to unload cash fast, ...) or slow down (partnering becomes more desirable than acquisition, 1st party development becomes competitive, various legal reasons intervene, business strategy shifts away from whatever made the acquisition interesting in the first place, org changes shift the focus away from the acquisition, ...).