Oh I remember the story.  Harmonix was happy to have GH instruments work on Rock Band and the other way around, but Activision wanted money (they stated they needed to be compensated for their technology). Considering how similar all the instruments are to each other, most of the gaming populace thought it was pretty retarded.  I still think it's pretty retarded.  Considering I own only Rock Band instruments, it keeps me from purchasing Guitar Hero stuff.

I give that post

The fact is, if your just merely wanting to play a rhythm based game...Rock Band has the better library of the 2.

Sqrl - Lets take the editor modes out of it, and talk merely about library versus library - the instruments are very similar to each other (RB2 vs. GH:WT)...Which one has the better library?

Rock Band:
58 Songs on Rock Band 1 (100% compatible with RB2, and without disc changing)
84 Songs on Rock Band 2 (100% compatible with RB1 suite instruments)
192 Songs for Download (100% compatible with RB1 and 2)
___________________
334 Total songs available for play with all instruments when RB2 launches. 100% compatibility between both RB1 songs, and RB2 instruments and product.

Guitar Hero: World Tour:
83 Songs on Guitar Hero World Tour
0% Compatibility with GH:WT instruments and Guitar Hero 1/2/3/Aerosmith games.

So if you are a Guitar Hero 1/2/3 owner, you have no compatibility with the new game...At all in terms of songs. You get your 83 songs + whatever DLC GH:WT gives you, and you've wasted your money on GH1/2/3 since nothing will work with the instruments.

On the PS3 it works both ways, on the 360 I'm not 100% sure but I would think so since the PS3 version does.

The nice thing about the editor is that its not just the editor. I agree if it was just the editor it wouldn't that great, afterall how many people really want to fiddle with it for 45 minutes to play one good song? But the GHTunes community really opens it up so that you're able to get songs from the crazies who spend way to much time on it (and actually know what they are doing). These songs may not be available within the first hour of getting it home, but I would be surprised if it took more than a day or two for the first batch of high quality songs to hit the service...and really does it matter how many songs you have on day 1?  I know I'm not going to be able to play through 80+ songs in one sitting (not to mention any of the paid DLC I might be interested in) and that is true for both games, there is way to much content for someone to complain about running out in the first 48 hours...because if they do..they need to get some sleep...and a job...and a girlfriend =P

I'm not gonna fault anyone for knowing what they like either, but I do think people should know what they're getting and what they're not getting.  A lot of info out there is flat out wrong and misleading from both sides.  And there is some info thats probably not out for both sides as well. There are certain things I know about World Tour that are still "In the works" but I'm not going to try and sell someone on a point that I know isn't confirmed yet.

This is a good example of the missinformation I was just referring to.

World Tour instruments will work with previous versions of the game (ie the guitar) just fine.  Also, GH3 DLC will be supported in World Tour and all future titles like GH:Metallica.  People who purchased GH1/2/3/Aero/80s will have compatability and their money is not wasted.  This is completely false FUD.

The ironic part of this comparison is that its made from the assumption that the person owns RB and ALL of the DLC.  But I've already said people who have RB1 on 360/PS3 and own DLC should pick RB2 anyways.

Honestly I'm not sure why you want to exclude the editor from the equation, that is a very real part of the decision people will make...how does it make any sense to ignore it?

PS - To answer your question I think both libraries have some great songs, but if I had to choose I definitely think GH:WT wins...thats just my personal preference but I love the CCR, SMB, Eagles, Van Halen, and Hendrix, songs they've chosen etc..and they still aren't done revealing the list.  But its just my preference, I don't think declaring one library to be objectively better than the other is reasonable.

Edit:

Few notes: 

-Its actually more than 85 songs, here is an excerpt from the press package fact sheet taken from GP 5 minutes ago:

"An Original Set List that’s Truly “Everlong” – Guitar Hero World Tour features the largest, most diverse on-disc set list to appear in a music-based video game. Comprised entirely of memorable master recordings from some of the greatest artists of all-time including Van Halen, Linkin Park, The Eagles, Sublime and many more, Guitar Hero World Tour delivers over 85 tracks for countless hours of rocking. In addition to the killer track list, the game will feature rock icons such as Hayley Williams of Paramore and Travis Barker of +44 and blink-182 and a collection of many other superstar musicians making their video game debuts on the Guitar Hero stage."

-GH3 DLC will work in GH:WT - Source

- The comment about DLC working going forward was from one of their recent demos it was either E3 or their press event, but it came from Brian Bright in response to an audience question iirc it was from someone at 1up asking the question.