The Vivtar, Sunpak, RL suk. No power. Barely enough for macro. The Sunpak DX-12R isn't bad, though. And, sadly enough, the new Promaster ringlight is kinda cool. A friend of mine got one and it wasn't too bad.
I'm gonna use a ringlight for portrait work...Elinchrom or Profoto. At least a 2400-3000WS of power, though. The new Elinchrom RL, with the Ranger power pack is killer. Tons of power!
Nowadays, Vivitar ANYTHING sucks. Hard. Really hard. Hell, the guy that started me shooting used to (25 years ago) have Vivtar Pro everything. Nowadays, it's all plastic and crappy. You don't want to know how many 285HV's I killed before going Metz!