A class on safety and proper use, plus some time at the range renting a few pistols, will tell you a lot. A pistol that feels good in the hand is a good place to start, but firing the gun can tell you other things simply holding it can not... How it feels in recoil, how sharp the recoil feels... My fiance has ruled out a couple pistols that felt good in the hand, after firing them. Things like not enough texture for a secure grip, and more felt recoil were reasons cited.
One thing that some people don't consider is slide manipulation. They feel the grip, pull the trigger, and find something they like, then find that the effort to manipulate the slide is too much.
Being able to quickly and easily manipulate the slide is important. It ensures you can load the pistol properly, and it is important for correcting malfunctions/jams. You don't treat the pistol gingerly during malfunction drills.
My fiance loves her CZ75, but she has trouble manipulating the slide quickly. She can use it well enough at the range, but I would not want her to use it for defensive purposes. We got her a Sig P320 for that... (excellent pistol BTW, worth a look, Running around $550)
BTW... is there a budget?
Others pistols to look into, all fitting between $500-650:
Walther PPQ
Smith and Wesson M&P
H&K VP9
Springfield XD/XDm (I have seen the original XD going cheap on some sites, as there is a new version just released, and they are dumping old stock)
Some cheaper but still good options:
Canik TP9 SA
S&W SD series
Ruger SR series
For the ones you mention...
As was said, the Beretta has a long trigger reach, it can be hard for some to use due to that. If you can reach the trigger in DA mode, and can pull it smoothly without straining, then it can be a good pistol.
If you go with a DA/SA like the Beretta, be sure to practice in both modes of fire.
If this pistol is not for concealed carry, then look at the Glock 17 as well as the 19. The 17 has a longer slide and grip. Adding capacity and sight radius, it has a little extra weight so that can help recoil. The 19 is chosen as a compromise most times, as it is large enough for a full grip, but a little smaller for better concealment. If the grip has changes other than length that would affect the feel, I do not know, I am not a Glock guy...
Look into the Gen 3 and Gen 4 Glocks. The gen 4 has a smaller grip, and adjustable backstraps to alter the feel. Some just prefer the Gen 3 though.
A revolver can be a good choice, but don't get an light weight version unless it is for carry. A medium or large frame .357 can be a good choice, and you can use milder/cheaper .38 for the bulk of your practice.
If you go semi, I recommend 9mm, its effective as a defense round with proper ammo, its cheaper to buy so more practice, and it has lower recoil and higher capacity. (unless you live in a state forbidding hollowpoints, so a larger round may help... but they all are handicapped, more so without HP ammo)
45 pistols tend to be on the large side, and harder for some with small hands to use. A 1911 can be comfortable for most people though, but I don't recommend one for a novice shooter.