I'm also currently a bit torn about this (except with ventures and 8.38 boards).
In my experience 8.5 trucks definitely feel more stable, wheelbite less, lock into grinds better and are just a bit more comfortable in general.
8.25 trucks do have slightly better leverage for flip tricks, makes flip tricks that I struggle with a little easier. They also turn a bit sharper which is important for ventures. The wheels jam a bit less for nose/tailslides.
Its a bit harder to aim and hold grinds, especially on chunky ledges. And I notice myself falling off my board a lot more when I don't land perfectly centred. This seems to be partially due to wheelbite and partially due to the trucks just being a little more tippy, little less stable.
Will probably need some more time to get used to the 8.25 trucks, but if I grow to prefer it (I do have 3 washers on the inside to pad it out), I could maybe see myself running them on 8.5 boards to make the extra board a bit more manageable.