Know this is the age old question but planning for 55km and 50 mile ultras summer/autumn. One is Lakes and mixed and rocky trails with some tarmac and the other cliff paths, some sand, some fields and some tarmac.
Looking for the elusive dream ultra shoe. Light (ideal is 250gm approx.), flexible (I like to get on my toes) but with a rock plate for protection, reasonable cushioning (but not losing all ground feel - so don't fancy maximal type), roomy toe box, ok grip - but manage the tarmac stretches, wear enough to last 500 miles+, low drop (4mm ish), fore/mid foot striking.
Inov8 Trailroc 245's - ok but bit inflexible in forefoot (stiff rock plate) but (!) uppers split after 100 miles
NB Leadville - very comfy but just that bit too heavy and clunky
Brook Puregrit - slipper like and flexible but bruised feet after 20 miles+ (no rock plate) and wear suspect ... and no grip at all on wet rock/wood.
Split between Peregrine 6s and Inov Ultra 270s as next attempt. Need to get it right this time
Wish there were more reviews on Web for shoes after 200 and 500 miles - rather than "out of the box".