personally I like the kriss , it look cool and it has every positive thing for a pro gun but....
well it doesn't have an edge. close and far combat it suck ( don't flame me for this , this is how I feel).
M4a1 is much prefer for close and far combat , the silencer is great for head shot cause it take a while for them to locate you.If you love 1 shooting take the m4a1 , sprayer go for kriss