Don't know if Antec is the only brand to buy, but out of the 6 or so brands I have around here, they have the highest overhead for current surges and best regulation at surge time, which is most important for that power up time.
We use a test jig to put a load on power supplies and Antecs' typically sustain %130 of thier capacity before they crowbar (this test is done for 15 seconds, which is our internal requirement for a power supply).
Thier rise time is very fast as well (the time it takes to reach output requirements).
Overall, a quality power supply. The only we use now.