What an interesting question. Yes I have heard Rubsams recordings of the sinfonias and they are very pleasing.
Most harpsichordists that I have heard use a certain amount of rubato in their performances. The harpsichord does not have the dynamics capabilities of the piano, and it can't articulate or accent notes in the same way the piano can. Because of this most harpsichordists use these rubatos or gasps in their play. I think the Baroque rubato is very different then a chopin rubato for example, but I think its still their.
Also the same technique applies when playing on instruments of weaker quality or in concert halls with poor acoustics. I believe that I read that Glenn Gould used this technique in concert performances because of poor acoustics (from the book Music and Mind.) I bring up Glenn Gould as he supposedly disliked the performance with excessive rubato, thought some of his early recordings have it too.
Personally I imagine my baroque performances with some of these rubato's, gasps or hesitations. For me this is really a baroque sound. Like anything else it should not be out of taste or interrupt the flow of the lines or voicing (harder to do).
I've seen a lot of CD reviews that don't like the extent to which he uses rubato in his recording of Bachs Inventions and Sinfonias. I'm interested in knowing what people here think. Personally, I think Rubsam's version of the Inventions and Sinfonias is very pleasing to the ear since I don't like how mechanical (and fast) others play them. My brother studied under him (Rubsam) at Northwestern University and from my discussions with him (my brother), I understand that performers of Bach's time and Bach himself probably held the first note of repeated paterns slightly longer. Of course we can't ask him (Bach) and I would have to ask my brother again for what evidence he has to base this on. I'm currently learning to play the Bach's Inventions and Sinfonias and think they sound much better when played with some rubato, however maybe not with as much as Rubsam uses.