From our experience till now as an independent 3-rd parity design and manufacturing of mining gear:
The top companies that delivered chips on time and as promised are Spondo and Avalon (except Gen1 that was a notorious mess)
Bitfury were great until Niko(BFSB) was selling chips, then in Jan 2014 they cut the sales of chips and floor the gas to build own mining farms and serve only 1m + SUD customers.
The best chip documentation for independent design was made by Avalon and Spondo again. Bitfury Gen1 and 2 had almost no documetation just random Bitfury's posts in the form of Q and A
AM was ok with Be200 , but 50% of the chips were garbage.
Bitmine were ok until Zefir was involved. I will do business with him any time again. He even managed to save our project in face of Avalon 1 failure