The most succint answer I can give (I really ought to come up with a canned version)!
Touring Plans - has canned touring plans, crowd prediction calendars / recommended parks for each day, place you can upload your own plan and put it on a map. Around $8 for a year, or free if you purchase the Unofficial Guide to Disneyworld. No forums. Not really any info on the site about the "whys" of the attraction order, so can be problematic if you get really messed up in your touring (for example - you might not be able to easily move the #3 recommended ride to the #10 position without waiting in long lines). I think the plans work well though - I don't use them any longer, but have in the past.
TGM - sample plans, but not exactly the same as a "canned" plan - more of a starting point for making your own plan. Recommended parks for each day, broken out into AM and PM, much more of an online book with an involved user community. Good forums with lots of support for TGM's touring approaches (vs. here on the DIS where there's tons of info - but you get a lot of different ideas on how to do things - TGM forums are more to support his philosophies). Cost $20 or so for one trip's planning. There's a lot more time invested using TGM because a lot of it is about learning how to efficiently tour the parks vs. just creating touring plans.
RideMax - creates a custom plan for you based on what attractions you want to see, what time you're arriving/departing for the day, etc. It's highly automated and gives specific times for arriving at each attraction, how long it takes to walk to the next one, etc. Price (can't remember) - $20 ish for 3 months, $40 ish for a year. No forums. Also has recommended parks for each day. So the easiest way to have a customized plan, but you need to follow it fairly closely to be successful, at least for the morning hours. We followed it to some extent on our last trip, just because I wanted to try it out. I thought the estimated wait times in their plans were pretty accurate. A few things they recommended I didn't do, because I didn't agree (but I have lots of trip experience to back up my opinions).
There are fans and detractors of all three. I know TGM and RM offer money-back guarantees, not sure about TouringPlans.
I have used all 3 - TGM works best for me and my family.