Boy, is *that* a loaded question!!!
First question:
Would you recommend spending the money
Well, it really depends on how much money you're willing to spend for a vacation, and what's important to you. I'm currently signed up for my 3rd
ABD, so obviously I think it's worth the money. Having someone else worry about arranging all the details, getting you access, arranging special activities, shlep your luggage, check you in & out of your hotels, transport you both to & from the airport, and everywhere in between, take care of problems that occur during the trip, reschedule things if needed, provide you with water and snacks throughout the trip, lead you on hikes, arrange people to explain and enhance what you're seeing, etc, etc... Well, it's worth it to me.
and which trip should I plan as my first?
That's really going to require a LOT more info from you. Single? Married? Kids? How old are you? How old are the kids? What kinds of activities do you enjoy? Are you looking for something "close to home" (assuming you're in North America)? Europe? "Exotic" like Asia or Australia? What time of year? Do you prefer active trips or cultural or nature? Museums or the mountains? Shopping or biking? There is a LARGE range of trips offered by ABD, and a lot of people here can give you insights on the pluses & minuses of certain trips once they know more about you.
There's some who have been saying they think the quality of ABD has been going downhill. That hasn't been my experience, but I'm sure you'll hear about both sides of it. Also, last year ABD had a lot of stumbling due to having expanded just before the economy crashed & burned. I think they are dealing with that.
Long way of saying, it can DEFINITELY be worth the money depending on what you're looking for. And we can help you with picking a trip once we know what you're looking for!
There's a sticky at the top of this forum with links to people's ABD Trip Reports. I think reading those will also help answer some of your questions.
Sayhello
PS, they are advertising
Adventures by Disney at WDW? Cool! I've never seen that when I've been to WDW. I think it totally makes sense, and never understood them *not* doing it!