There are far too many variables for anyone to provide a clear cut answer.
If you buy a good quality kit from reputable vendors, e.g., Winexpert, RJ Spagnols, Finer Wine Kits, you'll get a good wine every time. Kits cut a lot of variables from the situation, so the result is pretty much guaranteed, assuming the winemaker uses good hygiene and good process.
White juice depends on the quality of the grapes and the processor. Good quality juice will make wine at least as good as a good quality kit, possibly better.
Red juice? I agree with
@Rocky, you're not going to get a heavy red from it. Best will be medium body, which is fine if that's what you're after.
Red grapes? Like with white juice, it depends on quality, and the process of crushing & pressing your own grapes adds uncertainty to the process. These can be very good, although there's a lot more effort required. Must buckets are about the same, excepting the crushing is handled.
Good quality red kits with skin packs have become a close second to fresh reds. I prefer grapes, but kits lack the uncertainty.