A frequently asked question around here that seems to have come up every month or so in the 20+ years I've posted here has been " what is the best..... " or " what should I recommend for ..... ". Invariably many posters will chime in with their particular preference and why it is the best for them. This does not however give the new shooter much guidance as it does not take into account what is the best for you. A handgun is a very personal thing. What works for one person or purpose may not work well for someone else. If it's not right for you, it is the difference between driving a stick shift chevy pickup and a finely tuned luxury car with air shocks and automatic transmission. Sure, one can learn to drive either, but one can also get better results faster when one is using the right tool for the job. I have owned many many styles of pistol over the last 40 years and from nearly all major manufacturers. The photo below is just an example of what I use regularly now.
First, Pistols come in several sizes and caliber. They range from very small to very large. See Photo:
At the top, is a Glock model 40 mos. It is a 10mm and it is very powerful. It is also very large and heavy. It is not intended for concealment and I use it for hunting and outdoors in the woods open carried. It is great in that role. This is an example of very large.
Next is a Sig P226 in 9mm. This is considered a large pistol. It is a full size duty pistol that I carry on a police duty belt. It is reasonable as far as weight and size for this purpose. It is extremely accurate. 9mm is a moderately powered cartridge that can be mastered by most people. It is not the best, and is weaker than 10mm or .40 cal, but is usually considered good enough for self defense and many police applications.
Next is also a Sig, but a P229 in .40 cal. This is considered a mid sized pistol. It is both shorter in length and height than the P226. It is more powerful than the P226 but holds fewer rounds. This caliber is also easy to master, but not as easy as the 9mm. It will have more fealt recoil but will deliver more energy on target. It is also a good choice for defensive applications. You will note that it has a flashlight . I usually keep this pistol ready for home defense and it serves as a spare pistol should my P226 become unavailable. I also have a .22lr top end for it to allow for inexpensive practice shooting and training.
Both of these are DA/SA pistols that offer a high degree of safety when working in crowded environments, yet are extremely accurate. There is a myth that they are harder to learn to shoot. This is untrue, it just takes the same practice that anyone would need to learn something new.
Next is a CZ P10c. This is also a mid sized pistol. It is in 9mm and is very easy to shoot extremely well. It's accuracy is the equal of the Sigs and that is saying a lot. I sometimes carry this pistol when doing detective stuff or off duty when a loose shirt or jacket can be worn over it. Like the glock it is a striker fired pistol and requires a rigid holster that covers the trigger guard for safety.
Both of these mid sized or sometimes called compact pistols offer a good combination of shootability and concealability. If one were only to have one pistol, something in this size range would probably be a good choice.
Next is a Smith and Wesson Shield 9mm. This is a small pistol. It is light, easy to conceal and carry yet still easy to shoot pretty well at closer ranges, say inside 30 yards. I carry this pistol off duty nearly every day during the warm months and quite often during the cold. If someone is looking for reasonable power and easy to carry, something in this size range would probably fit the bill quite well.
Finally, I have a Keltec P32. This is a very small or sometimes called micro pistol. This size range usually includes .32acp, .380 acp, .25 and .22. I choose the 32 because it offers extreme concealment as well as power and accuracy. .380 is tough to get good hits with in this size range as it has heavy recoil for the light weight of the pistol. .22 and .25 offer very poor performance in these short barrels. I've found that .32 offers a good compromise and that European ammo is significantly more powerful than US made ammo. We were getting chrono results in the 900+fps range out of this pistol with Fiochi vs Winchester at 700fps. Same day, same pistol. This is the gun I carry when I don't want to carry a gun or when something else is inconvenient.
My choices are my choices and yours may and likely will differ. All of the major and some of the minor manufacturers make good pistols. You can see that I am not married to one brand or style. If you are choosing or helping someone else choose, remember that they are not you and their needs or preferences may not be the same. One thing that I think is a universal truth is NEVER BE AN EARLY ADOPTER. Note all of my choices are tried and true designs that have stood up over time. None were purchased within the first two years of production and I have had zero problems with any of them. Companies do put out product as soon as they think it's viable and they need to recoup their costs, with rolling design changes as they find flaws. Let the other guy find the flaws so you can enjoy smooth shooting.
I hope this helps.