They have gotten generally good reports. At the moment, they are slightly backed up on orders. There was a very recent thread on that exact point (in the last week or so) on
332-428 Ford FE Engine Forum . What you should probably just do is cut a check to one of the reputable builders that we have discussed and ask him to find you a quality iron block. Regular FE builders have avenues to obtain blocks that the rest of us don't. But they can't always "perform on demand." It could take weeks/months to land just the right block. Then let them do the build for you.