Which windows youre talking about? Vista?
If Vista then no, youre wrong.
Vista have far better security than OSX 10.4 (I dont know about 10.5) but if you know how secuirty works, you know Vista's Shell is far more secure than OSX (which is based on unix).
Another fact: Vista manage RAM far better than OSX. With Superfetch and readyboost, vista is BLAZING fast. Its not a gimmick, you can get speeds 60% faster with 2gb SD card for ~20 bucks.
And on the last note which is pointless....Yes Vista did copy stuff from OSX (If you count in development time, remember Vista was in development for 5 years, while OSX have 'semi releases' every 1.5 years) See the feature in 10.0, 10.1, 10.2, 10.3 and 10.4.
In the end, it really depends what you want.