I looked into a website which listed the best publishing editions for music: http://bestsheetmusiceditions.com/.
I have also seen the Belwin-Mills Publishing and the Kalmus Edition (it says on the website that the Kalmus Editions aren't exactly the best). Which is the better between the two of the previous statement. Also, isn't Belwin-Mills Publishing owned by Alfred? Thanks you all in advance!
That is a very odd site - you click on the "About" and there's is absolutely nothing about who is responsible for it, or what their credentials might be, or why we should have any confidence in their opinions. There's an email in the "Contact", but again, not a word about the actual person(s). Strange.
I didn't realize that Alfred had taken over Belwin-Mills. Or maybe only part of it - after a bit of investigation of a couple of scores at Sheet Music Plus, it isn't clear to me what has happened.
I have an old Belwin-Mills Rachmaninoff collection, and now, at Sheet Music Plus, it shows up with the Alfred logo at the bottom of the front cover.
But, I also have a Belwin-Mills Chaminade collection (which, interestingly enough, says "Kalmus Piano Series" at the top of the cover), and if I look it up at Sheet Music Plus, it now has a Kalmus logo where Belwin-Mills used to appear, not Alfred. So, who knows....
In terms of quality, I'd place them around the same level. The actual physical production is pretty basic, to put it kindly, but the print is clear enough, and the editions seem based on fairly decent sources. The cheap, glued binding of the Rachmaninoff collection I mentioned is completely falling apart, but to be fair, it has seen a lot of use, and was inexpensive, so I didn't necessarily expect it to hold up. I should go get it spiral bound, I guess.
Off on a tangent - last time I checked, there is no complete collection of Rachmaninoff's transcriptions and arrangements, which seems inexplicable, considering his popularity. The closest thing to it I found was this old - former Belwin-Mills, now Alfred - collection. Maybe now that the copyrights have run out (I think), that will change and some smart publisher will publish them all in one volume.