I love SRM. Hell, everyone loves SRMs. Nothing beats getting your ion of interest and identifying it with 1) retention time 2) mass, and 3) fragment ion(s). The problem is that they are sloooooowwww. If they were fast, everyone would validate every observation they made with SRMs.
That's why this paper in MCP lab from Amelia Pierson et al., of the Koon lab is so cool!
Parallel reaction monitoring uses the targeted multiplex MS2 method on the Q Exactive and lets you get a bunch of SRMs (or MRMs) all at the same time. Not only is it faster, but because the Q Exactive has an inclusion list of up to 5,000 ions all selectable by retention time, with the right chromatography system you can validate hundreds of observations in one go. MS based virtual western blots, may actually be a reality!