First off, the 9mm is the most popular carry pistol in the world - it doesn’t really need a case made for it. And, there will be pluses and minuses with whatever size of pistol you choose to carry. It boils down to personal preferences and your circumstances.
Found a Nano on sale NEW for $275. At that price it was a good deal. Bought it for my daughter.
Problems right from the first round down range. Rear sight fell off, okay I put it back on and tightened it down, stuff happens. Then about a month later it falls out again this time I cannot find it. Called Beretta and got a new rear sight, except it also fell off since they did not think to send it with set screws. I went after market and found one that had to be tapped in place, very tight fit and it came with a set screw. Real nice sight, even adjustable, but it hangs a bit over the slide. Honestly, the rear sight is irrelevant in many ways since this is a up close and personal pistol. Beretta would have been better off with fixed rear sights. While it fit my daughter’s hands really well, without the extended magazine I cannot use it. Oh yea, next problem. Finding accessories for the damn thing. I found one extended mag at Eastern Outfitters in their on sale junk pile, none at gun shows and found the second one at a gun store in their on sale junk pile. No good holsters available, at least not the type I like. I will have to have one custom made. With a striker assembly and one in the chamber I prefer a solid holster, hard leather, to cover the trigger while carrying. I prefer to carry outside the belt. Personal preferences, old and set in my ways.
Once I worked out the issues, it shoots well. In a self defense situation pointing at center mass it will do the job. My M1908 .32 is a far better pistol, way more accurate beyond 10 yards and my daughter prefers it. But it was sold in Chicago in 1926, is an antique and too valuable to have it end up in some cops collection after it is used in a self defense situation. Nearly 95 years old and shoots like it just came out of the factory. Doubt my Nano will be around that long.