"Best" is a discussion that typically evokes a lot of personal opinions.
Most average folks find the smallest .380's and the 5-shot snub .38's to be difficult to shoot, meaning accurately and controllably. Especially the lightest weight 5-shot snubs, since they produce more felt recoil.
I spoke with an established trainer who was assisting a large PD develop a pilot program for issuing 5-shot snubs for secondary and off-duty roles. During the development phase, testing of assorted officers revealed that the use of the modern +P loads produced some accuracy issues for the officers, especially when some demanding conditions were being used. Then they tried some old-fashioned 148gr target wadcutters. Shooter accuracy & controllability greatly increased ... as did shooter confidence. Last I'd heard, they were looking at adopting the mild TWC loads, although I lost touch with the guy running the program.
Sol, what's 'best'? Choosing the snub (all-steel or lightweight) and ammunition that enhances shooter accuracy and controllability, or choosing ammunition which makes it harder for the shooter to get accurate, effective hits ... even under normal range conditions?
Me? I tend to use one of 2-3 different +P loads in my +P capable snubs, and some various standard pressure JHP's in a snub built on the older Airweight frame (before being rated for a diet of +P). I've found my own balance of accuracy and controllability using the ammunition choices that have been available to me.
Would I still carry one of my snubs if the only ammunition I could find was a 158gr LSWC or 148gr TWC? Well, it's better than 158gr RNL or 130gr Jacketed Ball, I'd think.
Accurate hits matter, and being able to better place accurate hits in anatomically effective areas are arguably easier if the shooter doesn't have controllability and excessive recoil problems. You'd hope, anyway.
My pair of LCP's have typically seen Speer GDHP, Rem GS or W-W T-Series. Why? Because those were the loads available to me. Sure, I've tried some other loads, and while they all feed/fire in
my LCP's, in
my hands, I prefer using the 3 loads first listed. I'm almost out of the T-Series, though, and won't pay the cost of even the individual officer pricing, so it's the Speer and Rem loads I commonly use. (Whichever box is handiest when loading a magazine.) Now, the .380 is what I consider to be on the lowest rung of 'marginally adequate', and IF a JHP expands, it can come at the cost of penetration.
I tend to choose a 5-shot snub for the bullet weight advantage of the .38 SPL loads I prefer. The LCP .380 is a second choice, for when a jeans pocket might be a bit too short and small to accommodate one of my snubs.
That's me. Everyone has to determine such things for themselves. I arrived at my own choices over the course of many years serving as a LE firearms instructor an armorer, and having followed OIS and other shooting incidents.
There Ain't No Such Thing As A Free Lunch (TANSTAAFL), though, and not everyone will agree on what may be an acceptable compromise.