What you are asking is tricky because some of the best juice 'pails' ARE the high end kits - like Mosti Mondiale's Meglioli and Master's Edition kits are not-from-concentrate, all-juice kits, and they are appreciably better than Mosti' AllJuice kits (which are also not-from-concentrate). Also, the frozen juice pails that Mosti sells (Chile Fresco and Sonoma Edition) are not from concentrate, and there is some debate about the relative merits of those buckets against high-end kits.
That said, I know there are a number of other brands of juice pails, but I have no experience with them, so I can't comment about the quality compared to other ktis. I have read a number of posts of ideas and 'tricks' to enhance or improve some of those juice pails, but the only 'tweak' I have used is to add raisins to a juice bucket to increase the mouthfeel, tannins and (slightly) the alcohol level.