We use the data compiled from the USPTO patent and patent citations concerning the patented knowledge intensive technologies in three areas: cryptography, image analysis and data processing/software. The data is restricted to those patents between the years 1980-2003 that have two or more assignees, i.e. we consider only joint patents. We find some evidence that technological or product market proximity of partners in R&D alliance matters but whether the closeness generates more or less valuable innovations depends on the technology field. Our data further suggest that the most valuable innovations are generated when there is a certain level of prior patenting experience of the individual innovation partners. Interestingly, the prior patenting experience of the pairs of firms filing the joint patent does not seem to matter. It thus seems that learning from the prior joint patenting that creates more value for innovations is rather firm-specific than alliance-specific. Our findings on prior joint patenting experience generally hint that not only strategic benefits, and those benefits related to the management of joint patenting, can be gained from the R&D alliance experience.