I get the GE, 12 at a time for the discount, at 1000bulbs.com. They have a longer rated life than the PlusRite and have a better light output. They've never arrived damaged.
You can get the ballast kits from 1000bulbs.com for the same price with shipping, less if you order more than one, then you won't have issues if you need to warranty return something.
I bought those ballast kit before. I find they don't last as long. Advance transformer and ignitor last longer. Someone told me that advance cost so much more because they use more copper and less aluminum in their secondaries. Whatever that means. Obvious advance name brand also cost more since they are made in us and not china.
Here are some of things I bought for hubbell 320w lights through ebay: