Per question a few posts back, I religiously ride the DLX 8.25/14.38. Prior to 8.25 trucks being a thing, I rode it with 149s. Once 144s came out, I have ridden those. However, I have dabbled with 149s on several occasions. Here are my experiences with both (w/53mm Spitfire Classics):
Magic Carpet v. Hot Rod
144s: Slight magic carpet on wheels. Axles flush to deck.
149s: Axle nuts slightly hot-rod. Wheels are flush to deck.
Turn
149s absolutely have a better feeling, and more stable turn, IMHO. The lateral wheelbase of 144s just doesn't seem to have the same "magic" as 149s, and the 144 turn feels more...cramped, tight, and less fluid/fun.
Grinds
I do not like the feeling of "cross locked" grinds on mini ramps or street. Also, when doing any type of 1-truck grind, I want a good lock-in. With 149s, I notice more of "lateral slop" with grinds. Cross-Lock feel more exaggerated when I end up in one (which I do not like). 5-0, nose grinds, hurricanes, etc. seem to "float" a tad before finding their groove. I don't like my trucks to have lots of lateral movement getting-into/during grinds, and I feel that 144s have less of that than 149s, which is a good thing for me (whereas 139s feels way too tight-rope). 144s are the perfect medium. With crooks, like someone else said, I like my weight a little more inside than outside. So, here, too, I like 144s better. Oh, I can Smith grind better on single-sided ledges/ramps with 149s, however.
Weight Distribution / Center of Gravity
Here, also, I feel like 144s cause me to keep my center of gravity more over the center of the deck. I do a ton of feeble to fakie, pivot to fakie, axle to fakie, nose pick to fwd, etc. type tricks on mini ramps. Here, 144s also seem to keep me more centered over the middle of the deck during the balance point and reentry.
Flip Tricks
They seem easier to flip on 144s, but the landing on 149s feel more stable/solid (which makes sense, because overall 149s feel more solid/stable).
Weight
My board def feels heavier with 149s.
Overall, I stick with 144s. Are these differences real, and substantive enough to create any actual differences, or are they just reality because perception can become reality? That's for you to find out (and post about in the Madness thread. Lol.)