Im a prime member as well love Amazon...
I just got the Apollo kit you should look into them. they come with nice rop ratchet hangers (i know thats not a big dea but its a nice perk) and a 1 year no questions asked warranty on thier bulbs and a 3 year warranty on thier ballasts.
ill be ordering a new Appollo 400w ballast after the hollidays and i am currently using a 1k w Apollo ballast in my flower tent. I dont know much about the Ipower brand so i cant really compare but i am impressed with the apollo brand so just wanted to shout that out might be worth a look especially if the Ipower ones dont come with a warranty.
I had a broken MH bulb when my kit came in and no warranty card. I contacted the seller and he sent me a new bulb and card and i didnt even have to return the old one.
also when i got the warranty card it had a promotional free bulb offer, just had to leave a review on amazon and they shipped me a new 1kw HPS bulb for free was pretty sweet....
anyways thats my experience with apollo, not trying to suggest you buy thier brand instead just throwing it out there for you to look into if you havent already.