I have heard negative things about most all companies you mentioned, but I always take them with a grain of salt.
I just recently got a whole front end for my 50 Plymouth 2 dr wagon from Fatman. The parts are top notch, welding is very good, gussets where they should be and fit is right on. Of course when you fit, you always have some wiggle room for adjustments.
You didn't say what vehicle you are putting the parts on, but I do like the Fatman stuff and quality is very good.
Heidts is the only one I'll ever use. They're materials are top notch and are easy to install.
Eliminating the strut rods will over time weaken the lower "A" arm attachment point. The crossmember needs to be fully boxed from one side of the frame to the other and extra gusseting added to the eliminator or cracks and failure of the lower "A" arm attachment will result. Do a search here and there are a couple LONG threads about this happening. There is nothing wrong with the Mustang II IFS as Ford designed it. They spent millions to come up with a reliable design. Its just when entrepreneurs decided to mess with a proven design (like eliminating the strut rods) that things start failing and give the design a bad name.
personally i prefer TCI kit over fatman fab i currently have both kits on the road on 2 different 39 chevy sedans the TCI kit i installed what a breeze bolt in the crossmember and the rest falls into place the fatman kit was already in the car not overly impressed with the kit but thats just my opinion many other kits out there hiedt's chassis engineering who by the way make one of the best rear spring kits on the market
I have never had a problem with Heidt's products. One feature to look for is the use of OEM style upper inner control arm shafts in whatever front end you purchase. The OEM style are knurled where they contact the upper spring perch. I have seen Mustang II based front suspensions have problems holding alignment settings when smooth faced upper inner control arm shafts are used. They can slip, altering the alignment.
For what it's worth, I have never had a lower control arm problem when eliminating the strut rod either.