Depends on what you need the Data Tracker to do in the scenario. ;) If they need to kill something, the Al'Fasid can drop a grenade on someone's head pretty easily. If they need to survive, then just a Keisotsu hiding in a corner works just fine.
I have been favoring the alFasid on missions where I need to kill something with the data tracker. It has a good toolkit with the HMG/SLGL/LGL load out. Plus, you get a zone defense mine to guard your backline as a bonus.
I like some flavor of Wu Ming. He's durable, good killer himself, doesn't run out in the middle of the road to get shot.
As do Brawlers. Especially now since it's one of 2 (really only 1) Lt. option. My opponents seem to go right for them now.
I haven't heard of anyone taking him in Ikari yet. Probably because the Al Fasid is better for less pts. I wish we got the Anaconda instead.