I wasn't going to say anything on this thread because you asked what was GOOD.
But maybe it won't hurt to steer you away from what might not be a good idea even though these things are cheap. Often go for price of shipping.
I didn't necessarily get burned (not out much money)... but I have my regrets around the system I built around Flashmaster AA 400 watt-seconds system.
There are three old models that you can tell apart by features:
ancient (two prong electric - vacuum tube trigger circuit)
really old (grounded main - solid state trigger but still only 4 outputs)
old (5 outputs because one of the 4 goes to two sockets one with 12v model light and the other umbrella 110v model light).
Then there are the new ones like they came out with an 800 Watt seconds version. I am sure they are fine.
I had been thinking of getting a Norman powerpack and heads but at a flea market an acquaintence had the Flashmaster heads and stands extra dome bulbs (no powerpack) so I gave him $50 and lugged away the giant suitcase. It was kind of funny since I parked my car a half-mile away. But I got it home and picked up one of the really old powerpacks for practically price of shipping. It worked but the two lamps with hard-wired bulbs didn't. Easily replaced and wired in. Worked fine for about a year. Then one day the pack burned up. I think I had left it unattended and powered on. So I figured I'd replace the powerpack and found an ancient one for price of shipping again. I think long term I was out less than $200 but I never leave the unit connected to electricity unattended. I isolated the trigger circuit from camera optically to minimize shock hazard (by wiring the camera to a flash aimed at a slave). But the ungrounded ancient model can't be grounded (or the 12v circuit shorts to the 110v circuit blowing all the modeling lights and smoke comes out of the capacitors - doesn't hurt it though).