i"ve owned a couple specimens, one for 35+ years. Have one in blue and one INOX (stainless). Most people that have them will sing their praise for a bunch of reasons...number one being they are just plain fun.
Detractors, (usually those who don't own them) will tell you that they don't want one because they don't have an extractor, but rather - relies solely on the blow back of the round to eject. Well, that's sortta true... if a casing happens to stick, there's nothing you can do, except lift the barrel and push the round out, or use a spent round's casing mouth to pry it out. I've heard of this over the entire length of my personal ownership, but never witnessed it happening...I suppose, because I don't use cheapo ammo.
Other posters have already said it, but, make darn sure you use premium ammo (particularly CCI mini mags, stingers, or velocitors) and you'll have no problems. If you use cheapo ammo, you'll probably become very discouraged by this little gun, sell it, and become one of its detractors.
Beretta also makes the 3032 in .32acp ... almost a carbon copy (3032 is slightly chunkier) of the 21A but in a tad more reliable cartridge