Having done nearly 800mi in my current Brooks Adrenaline GTS14s, I started a new pair yesterday. My right foot felt a bit tender in the arch afterwards, so I think my old pair were losing their support.
I ran both of my London Marathons in Brooks ST5 Racers, but with the insoles from my GTS inside, as I found that the grid-style underside of the ST5 insoles gave me hot-spots on the long runs. If you train in GTS I think they make a good light(er)weight alternative.
I've also ordered a pair of Mizuno Wave Inspire 11 to try for general training.
Today I have this workout scheduled: 8mi with 2 sets of 4x300m @ 800m to mile pace, with 300m recoveries and 4mins jog between sets.
Instead of running 300m recoveries, I've modified them to a time of 1:37 (which is about 300m at my usual jog recovery pace of 8:40ish) as I find that there's too much scope for skiving with recoveries based on distance.
Apart from strides, I've never done an intervals session with reps at anything quicker than 5k pace, so it will be interesting!