1. Ruger Security-9
2. Taurus G3
3. Canik TP9sf
4. Smith & Wesson SD9VE
5. 3rd gen S&W police trade-in, most likely a 6906
I've never shot or even held a Security 9.
I like my Taurus G2c quite a bit. If the G3 is similar, it's probably a good gun.
I have a Canik TP9. Isn't it a copy of a Walther? Mine is a good shooter. I got it used and the rear sight needed a little TLC, but I have had no other problems.
I had the 40 caliber version of the SD9VE. It went bang every time. The trigger was pretty bad.
My 3rd generation S&W is the inexpensive Model 915. It shoots just fine. I have no complaints. I like the balance. The DA trigger might be a little stiff, IIRC.
My CZ75 variants and Tanfoglio copies (sold here as the EAA Witness) are my favorite service pistols.
I got this little SAR polymer CZ75 compact "clone" NiB for something like $250 plus shipping. It is the second one I've owned, and I've liked them both a lot. They are made in Turkey.