I have a 430EX II as well and I was in a similar boat as you are in right now. I got a Sunpak PZ42X which works for what I need it to. It has TTL, but I prefer to use the 430 if I am going to do on camera shooting. It's just a more rugged unit. But for firing off camera with triggers the Sunpak works fine.
Using cowboy studio trigger. As far as power...I dont know I was really looking for something somewhat cheap , decent recycle , and to use as a fill for my 430. Which both are going to be used off of camera. I intend to use them for portraits of my family , maybe some martial arts stuff a, macro and whatever else.
The 285HV has more power than your 430. The 285HV has a thyristor and can be used in an automatic mode. The 285HV has a flash calculator built right into it making it easy to figure out the right settings for each set-up.
What units is the yongnuo GN number in, and at what ISO?
If they don't say, the GN number is useless.
The GN number a flash unit has describes how powerful it is. The GN number is given as either meters and/or feet, and tells at what ISO setting the GN number is valid.