Regarding the S&W model 10 with 5" tapered barrel vs the 4" heavy barrel, which one balances better and points better for you?

Have owned my 10-5 since 1987. With the tapered barrel, balance and target acquistion is easy. I usually practice and carry with 158 SWC HPs, and never had an issue. In 1988, I was issued a M66-4, 4in bbl 357 mag. The 125 gr Federal rds were a completely different round, and magnums to add. After a while, we started practice with the 38 Spec rds, and quals only with the 357. I'm not sure, but the barrel was a heavier bbl, and also pointed and aimed well, despite the 357 mag rounds. My M10 is a lighter firearm to carry, fixed sight also.

I certainly prefer the 5" tapered. You will probably find many on this forum who like the 4" heavy better, but I am not one of them. 4" or 5", the lighter tapered barrel moves faster and aims faster (because the sight sticks out more).

The heavy 4" barrel is probably better on a static bullseye target, where fast sight alignment from a draw is not an issue, and the stability of the heavier barrel is an advantage, rather than a disadvantage.

What points most naturally varies with the grips. I had one 4" K SB heavy-barrel (a 547) which pointed very well with the Goodyears I had on it (can't even remember exactly which model of Pachmayrs they were), but hands vary, too, so you will have to find out for yourself what points best. With the exception of that gun-and-grip combination, I would generally opt for the tapered barrel on a carry gun.

Also depends on weather you like the nostalgic look of the 5" pencil bbl. or the more modern heavy bbl. look. I like & have both.

I'll take a standard barrel over the heavy one any time.

Also the grips and type of butt you have on the gun can make a difference. I have a Model 64-6 (stainless version of the Model 10) that has a round butt with Uncle Mike's round-to-square conversion rubber grips. This gun has a 4" heavy barrel and it points perfectly for me.
I also have a Model 10 with 6" tapered barrel that has K frame diamond target grips and that gun has the perfect balance and pointability for me. Its very lively and quick in hand. I'm not sure how this gun would be if it had other grips on it, but I have larger hands and like the diamond targets.

One fellow on another forum said that the 4" heavy barrel and the 5" tapered barrel were perfect in terms of balance for a Model 10, and I guess he owns a lot of them. I don't know, as I only have my 6" tapered barrel M10.

The 4" bull-barrel Model 10/64 with service grips and a Tyler T-grip feels like it never wants to leave my hand. I'm sure the 5" pencil 10 has its adherents, but I've never seen one 'in the flesh.' That extra inch of barrel might make it harder to conceal, but I'm sure some folks would have no problem. More power to them.
I've never forgotten what Mas Ayoob said about the Model 10/64: small enough to carry concealed, yet big enough to look menacing.