If you had one "Built" that is probably why.  There are hundreds of shops that build hybrid Garrett turbos that are not on Garrett's website as something they build/sell.   
Forced Performance is obviously a better one but for every FP there are 100 terrible examples unfortunately. 
Jeff   
PS -- That being said, any turbo can fail for a variety of reasons but it wasn't hard to look back through invoices and know we had issues with 6 in 10 Precision's and 1 in 50 MHI or Garrett's.  Profit margin wasn't worth the head-aches...