I'm sure there are nicer guns out there. I've even handled and fired a couple like the USP that I definitely felt were "better" than my Bersa, but right now the Bersa Thunder 9 Ultra Compact is my favorite 9mm, because it's the one I have, and it was very affordable, and despite the fact that there are "nicer" 9mm handguns out there, I don't think there's one out there that offers a better value at the Bersa's price (about $300 new for mine).
It's DA/SA. The DA pull is smooth and not too heavy. It's accurate. The controls are easy to operate. The grip feels right. It's one of the most reliable semiauto handguns I own. My Bersa Thunder 9 Ultra Compact and my HS2000 (same Croatian pistol as the XD9) have never failed to feed with a wide variety of ammo. My brand new Springfield Armory 1911, by contrast, is the pickiest gun I own.
You may wonder why I picked the Bersa Thunder 9 UC over my HS2000/XD9 as my favorite 9mm. They're both excellent, but I prefer the Bersa as a carry weapon because it's more compact, and because I prefer to carry the decocked Bersa rather than the striker-fired HS2000/XD9. I know that striker fired pistols like the Glock and XD are "safe," but it's a matter of personal preference for me.