Bought the kingston kit looking for a cheaper deal than others on the market. Arrived in excellent condition and very quickly, along with the precision screwdriver kit also ordered. Installation was quick and simple, and despite warnings that the kit may not be compatible, it works perfectly, and is running as I type this. Packaging was excellent and looked fairly secure, also came with brief installation guide, with further links.
Small changes in performance so far, however, have yet to install heavier music applications (Logic, Sibelius etc) to see any big advantages.
Would definitely recommend the product, but as with any memory installation, requires patience and a precision screwdriver set.
[EDIT] On further testing and software installation I was very impressed at how smooth the above applications worked running next to each other and am glad I bought the upgraded RAM. Would've definitely expected much slower performance without it. [/EDIT]
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Installed on: 13" Macbook Pro (early 2011)