IMHO it comes down to what each individual shooter wants and is comfortable with. I personally prefer no safety on my Shield and thats what i have. However someone else may be use to having a safety. FOr me it comes down my training.

I have always trained to carry/shoot with a safety off but it depends on the gun as well. A 1911 yeah I carry with a safety sure. H&K USP 9/45 safety on because thats how I trained but the P2000sk I dont like a saftey. Ihave shot Glocks for years never felt unsafe carrying one. Same with the XD, XDM, XDS, M&P etc.

I guess it comes down to your training and philosophy