I have three of these (my sig )
It really pushes 90CFM without any thing blocked its airflow
It has ultra low static pressure (i think cm lie us on this...)
CFM will drop easily by low pressure

i on currently on fan survey..seeing the artic f12 is have quite good reputation but dun have any led..i need sumthing to light up my rig..thinking getting a cheapo led fan..but dun know if worth it or not..

depends lar bro, if u planning on using those cheap cm ones, i would advise to cut our the fan holes in your casing cos they dun have static pressure. better suggestion, get these artic fans and use either ccfl/led strips to light up your case. i then use dual wired diy led kits to give extra light in key areas.