Dunno about cooler or warmer (never use such terms), but Polish is more pleasant sounding and far more sophisticated. To many Poles Russian sounds primitive and peasanty as in "ja paszoł, on paszoł". In some Polish peasant dialects uneducated people also forget the endings and likewise say "ja poszedł, on poszedł, "my byli, wy byli, oni byli" instead of using the proper endings: "ja poszedłem, on poszedł, byliśmy, byliście, byli". In English it would be roughly comparable to "me go, he go".
Not to mention some vulgar-sounding word choice: Ona otkryła guby (reminds Poles of gęba) i skazała: u menia nasmork (the Russian way of saying "I've got a cold" but to Poles it sounds like she's full of snot).