Howdy
I usually like to buy Winchester brass, not so much because of price, just because there is usually a guy at the gunshows who carries it. I'm not too smart about the way I buy brass, I usually just buy a few bags at a time, rather than ordering a whole lot at a reduced price.
For 44-40 in a rifle, I definitely prefer Winchester, I have measured it and it is thinner than the other brands, which makes for better sealing the chamber in a rifle. Unfortunately, Winchester 44-40 brass seems to be in short supply at all the mail order houses right now. Winchester doesn't make this stuff all year long, they run batches several times a year. For 44-40 Winchester brass, everybody seems to be out right now. Dunno if the situation is the same with Winchester 45 Colt brass too, but I would not be a bit surprised.
For 45 Colt in my pistols, I don't really care what brand I use. I have a huge pile of 45 Colt brass I've accumulated over the years, some I bought as loaded ammo, some I bought as empty brass. I have everything in my pile, Winchester, Starline, Remington, PMC, and a bunch of other stuff I can't remember right now. Not familiar with Top Brass. Neither my pistols nor my loading press seems to care what brand of 45 Brass I put into them. It all loads and shoots pretty much the same, at least as far as I can tell. I'm not a precision shooter, so minute of angle accuracy from a pistol is kind of out of my league.
I don't own any rifles chambered in 45 Colt. If I did, I would probably be looking for the thinnest brass I could find for them, because the thinner brass will obturate to seal the chamber better like the pards have said. But for my revolvers, I really don't have any preference as to brand.