Here you may find a few examples (recent evaluations with more than 100 students seem to be rare...):
- Maree Gosper, Margot McNeill, Karen Woo et. al.: Web-based Lecture Recording Technologies: Do Students Learn From Them?, in In. Adelaide: Higher Education Research and Development Society of Australasia, 2007.
(interesting summary of several surveys down under in Australia with Lectopia/iLectures, more than 10.000 students addressed but only about 800 answered...)
- Marc Krüger: Pädagogische Betrachtungen zu Vortragsaufzeichnungen (eLectures), in i-com, Zeitschrift für interaktive und kooperative Medien, Oldenbourg Wissenschaftsverlag 3 56--60 (2005).
(first try of a more general study...)
I was not able to find a more general, summarizing report dealing with a variety of scenarios and clustering the results (inluding methodological soundness and decent empirical basis).
So...first thing -- if you know about any study or evaluation (with significant empirical basis), please write a comment with a link to the source (!)
Second -- I know that this will also only be a rather limited and primitive poll -- please fill out the small poll below. Maybe we gain a little bit more insight on student's satisfaction concerning online lecture recordings -- not only restricted to a single course or a single university....