well the zapco does about 2200w
the other amps listed do 5000w.............slight differance.
the zapco is aimed more towards super super clean signals and great SQ. In reality, you wont notice a terrible large differance in SQ unless you have really nice SQ subs and a perfect install.
the other amps you wont notice really much SQ differance in a typical install (as long as the signal isnt clipping). From the limited knowledge i have with these amps, the atomic 5000.1 will 1ohm daily with a good electrical. I'm sure the VFL will also do 1 ohm daily pretty well, however i wouldnt run any of these amps daiyl under 1 ohm. You will also need a REALLY great electrical system upgrades if you want to run any more than 2000w, none the less 5000w.
I'd look into a kicker zx 2500.1. They are very efficent, and VERY reliable. They'll run 1 ohm daily, but you can still run them at 2 ohm and get a great deal of power out of them. If you absolutly need 5kw, i'd look into heavgy electrical system upgrades BEFORE getting the amp.