In a polymer bottom gun the balance is acceptable at the beginning of a full magazine but as you use rounds the balance changes very rapidly to - top heavy.
This comment appears a lot in other threads and in many cases is true. But I have found polymer framed pistols where I find this mostly a non-issue. To be the balance issue only because an issue with a polymer framed pistol when you're talking barrel lengths >4-4.5 inches. I usually prefer a 4" barrel and I find my polymer pistols, HKs mostly, balance just as well as my metal handguns.