I donno, that description seems to me to capture in a general way most of what people have pointed to as the experience of (or lack of) free will. Searle might say that the experience of the lack of free will is the experience of there being no such gaps where we generally expect them. That is, the experience of anticedent causes or reasons being causally sufficient for an action in the way perceptions and the causes of perceptual experiences are causally sufficient to make me believe that there's a tree in front of me.
I mean, in some sense anyone who gives you an answer to the question 'how does it feel to have/not have free will', where 'free will' is understood as metaphysical free will (the kind that's at stake in discussions about determinism, say) is confused. Metaphysical free will or lack thereof can't feel like one thing or another. We can however distinguish between free will (in a non-metaphysical sense) and coercion, or free will in action and the kind of non-free relationship we have with our perceptual beliefs. And the 'gap' thing is a fair account of that phenomenological distinction.
Eh, I wasn't fair in my other reply. The idea of a gap seems like a neat one, and probably matches some of the free-will experiences, just not all or even a majority of them.
Given the spike in free-will debates on LW recently (blame Scott Aaronson), and the usual potentially answerable meta-question "Why do we think we have free will?", I am intrigued by a sub-question, "what would it feel like to have/not have free will?". The positive version of this question is not very interesting, almost everyone feels they have free will most all the time. The negative version is more interesting and I expect the answers to be more diverse. Here are a few off the top of my head, not necessarily mutually exclusive:
Epistemic:
Psychological:
Physical:
For me personally some of these are close to the feeling of "no free will" than others, but I am not sure if any single one crosses the boundary.
I am sure that there are different takes on the answers and on how to categorize them. I think it would be useful to collect some perspectives and maybe have a poll or several after.