I've used them both. Touring plans (and their "Lines" smartphone app) is an offshoot of the Unofficial Guide books. The books have been around for quite awhile, and have always featured several pre-set touring plans in the back of the book (one day, two days, for kids, then some for CA and I think Universal, too). But of course you couldn't customize it.
RideMax was solely an online enterprise, and it featured customizable touring plans where you could put in dates, arrival times, and what rides you wanted to do, and it would optimize the order and make a plan for you. You could schedule in breaks for meals, rests or shows. It improved on the Unofficial Guide books because it could suit your needs. Drawbacks were that you couldn't schedule parkhopping in, or specific shows.
Then Unofficial Guide came up with their own customizable app, Touring Plans and the Lines app, with a real-time updater from members in the parks, that gave you wait times, FP return times, etc. Kind of like the DL app, with a few more frills. Problem is, it's usually not as accurate as the DL app; I don't think enough members update from the parks.
I used to use RideMax, but Lines is pretty inexpensive and is a lot of fun to play around with when you're planning. So that's what I'm using this time. Maybe others can chime in with a more recent comparison between the two.
Hope that helps!