ATTQOTD: You have no idea what I can do with this topic, lololol! My ongoing search for the Holy Grail of shoes is the stuff of legends.

I can truly wear almost anything for up to 10 miles, but the wheels come off at double digits; my struggle has been trying to find the perfect marathon shoe. I won't go through the whole ridiculous saga, though - I'll stick to the questions posed
Do you have a pair of trainers and a racing shoe? Not really - I do generally have shoes I prefer for short runs vs. long runs, though. And I always prefer new, low-mileage shoes for racing; I like them to feel snappy!
Do you have a pair of shoes you only use for short distance races versus longer races or training runs? Yep - so far, my Newton Gravitys start bothering me past about 10-12 miles, so I've been reserving them for half-marathon or shorter distances, and Newton is my go-to for speedwork. But I'm really loving the feel and extra cushion of my Newton Kismets, so I may try taking them on longer runs. I could not find a shoe that wasn't torture past 15 miles while marathon training last year, so I wound up falling back on an old (but low-mileage) pair of Brooks Ghost 7s that I'd been using for theme park walking. They got me through my first full, so I bought a 2nd pair... and the 2nd pair has been nothing but disappointment. Tried the Asics GT-2000 4 and thought I'd found My Shoe... only to wind up with debilitating Achilles pain from them after a half. Planning for next January, the search has begun in earnest... again. ~sigh~
Current line-up: Newton Kismet (yay!), Asics DS Trainer 20 (not bad up to 6 miles), Asics GT-2000 4 (ouch!), Brooks Launch 2 (yay! for short distance, not sure I can go long in it), Newton Gravity III (yay! but needs to be retired), Brooks Ghost 7 (retired with grace.)
I train exclusively in Brooks Launch 2 now. I rotate 2 pair. I have an extra pair ready to be rotated in, but after that I'll probably have to go to the Launch 3 unless I buy more of the 2's on clearance. I also liked the original Launch and had 2 pair of those. I bought 1 pair of Saucony Kinvaras and REALLY wanted to like them. I tried running in them twice and got a heel blister and decided they weren't for me. I may give them another go someday, because they seem like the perfect shoe... but the Brooks Launch series might be the perfect shoe FOR ME.
Ooo, interesting stuff here! I, too, tried the Kinvara and wanted so much for it to work, but the shape of Saucony's shoes just don't seem to match the shape of my feet. I have the Launch 2 and mostly loved it at first, but it got a little spongy and seemed to lose its pep... but in a fit of shoe frustration I pulled them back out the other night and had a great run in them. So maybe? IDK...
Well, after all my research, I am convinced 'support' shoes are physically incapable of doing what they say given the enormous forces being applied. I've also focused heavily in getting my running dominated by my hips, glutes, and hamstrings, and off of my quads. So far, it's worked as advertised for me. My ankles aren't stiff anymore in the morning and my calves have stayed nice and loose. So until I test these out at 15+ miles, I'm pretty happy with them.
This is exactly where I fall, too. The more stability features in a shoe, the more muscle soreness I get. I've tried some stability shoes (on running store expert recommendation) that actually
caused me to overpronate to the point of causing pain, but I was totally fine in a low-stability shoe. BUT going past about 13 miles in my less support-y shoes just kills my feet, and where I do need a little extra support is in the ankle collar, thanks to an old injury.