Since there has been some recent conversation on tacos and some friends recommended a few places in the hood i decided to check a few out.
Came up with a surprising conclusion! See the end.
First up on the hunt...
Zacatacos3837 Harlem Ave
Berwyn, IL 60402
(708) 484-1300

While advertising "Authentic Char-Broiled Tacos" and I could see the grill in the back, the grill was cold and the cutup steak was dished out from a bucket of grease. While not too tough it was a touch dry. Not much char flavor.
Next?
Las Fuentes4101 Harlem Ave # 11
Berwyn, IL 60402
(708) 788-2002

While not a carry out type of place it came highly recommended and they were able accommodate my take out. The priciest of the group ($3 per) but it did come with all of the toppings (onion, cilantro, lettuce, tomato and cheese) and a good handful of chips and pico de guillo.
Excellent char flavor and fresh. Maybe charred a little too long as it was a bit crunchy. A little less meat that the others, possibly because of the extra toppings.
Heading west...
Las Asadas8863 Ogden Ave
Brookfield, IL 60513
(708) 485-8250

As I walked in and looked into the back I saw the grill filled with steaks and my mouth started watering. Placed my order and kept an eye on the kitchen.
Boo! He grabbed the tortilla and reached into the bottom of the 'Bucket of Grease' to fill and to make matters worse he popped it in the microwave to put a bit of extra heat on it (causing the outer tortilla to stick to the paper).
The meat was rubbery but the 'Bucket of Grease' managed not to wash off too much of the char flavor.
Heading home and back east we had time for one ore stop...
Zacatacos6224 Cermak Rd
Berwyn, IL 60402
(708) 484-8443
(708) 484-8460

Sorry for the blurry photo!
By far the biggest taco for the money! After placing my order it was brought up to the counter in minutes dashing my hopes for a fresh charred product and diving in it had the highest 'rubber' quotient and least char flavor. Filled me up though.
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My conclusion? Most of these places will char-grill the meat but after cooking it will end up in the infamous 'Bucket of Grease' dumbing down the char flavor and if the heat is high enough, boiling the meat to bring out the rubber texture. Not a rubbery-ness of gristle or fat but of a meat incorrectly cooked (or in these cases, held).
In most cases it will be a matter of timing. How much time spent in the 'Bucket of Grease'.
We should be seeking out places that grill the meat fresh to order.Las Fuentes was the hands down winner even if it was charred a bit too long.