I think for me, price and warranty has the least to do with the decision.
Pretty much all 7.3L injectors, similarly sized, are within a few hundred dollars of each other. That may be important if you are on an extremely tight budget, but it may come back to bite you later if you make a decision based solely on price.
Warranty is only as good as the person standing behind it. This is why reputation is the biggest factor for me. As stated above, if a part is going to fail due to manufacturer defects, it will be in a relatively short period of time. This is why warranties do not need to be extremely long, in my opinion. What really matters is that you can get the seller/manufacturer to work with you, should warranty ever become an issue.
Reputation is key. With reputation, the sales will come, regardless of price or warranty.
Keep doing what you are doing Tim. It is working just fine.