I can't say anything for anyone else, only what I've been through.
I haven't tried Airtex, but I tried some other aftermarket brand I got on ebay. Let me tell you folks, these guys here knows what they're talking about. I read somewhere here about the pumps for these Chevys. About not getting anything but Acdelco or Bosch because of the pressure problem. I was in a pinch and went ahead and got the cheap ones. It starts out fine for about 6 months, then craps out in about a year. Those pumps cost about $100 at that time each. I went through about 3 in 3 years. I even got just the motor and swapped it out using the same housing. I learned, after my 2nd one, to let it prime for about 2 seconds then crank it. Otherwise it will turn about 2-5 seconds before it starts.
I finally found an Acdelco for about $200 and broke down and got it. It's been over 3 years with no problems. Starts with 1 crank consistently without priming it for 2 seconds. If I had only listened, the time I would've saved not to mention money.
The factory one crapped at about 75,000 miles. But I always drove it down to E. I was thinking doing so would get any moisture out from the fuel. Now I fuel up at 1/4 tank. I suggest to only get Acdelco for these Chevys.