There are lots of pro's to endurance riding.  But, since most endurance 
riders are masocistic, we don't recognize the con's.  Depending on how you 
budget you $, it should not cost any more than barrel racing unless you win 
at barrels all the time and recoup your expenses in prize money.  See, 
there is virtually no prize money in endurance riding and there are many 
reasons why there should not be any.
My suggestion to you is to volunteer at one or two rides before you go out 
and buy the "suitable" horse.  The endurance home page has the ride 
schedule in your area or you can e-mail me and I'll send you a list of 
rides in your area.  I think that's really the best way to test the water.  
Ask lots of questions at the rides, endurance people love to talk about 
their sport.  Once you're sold then think about getting a horse.  You might 
be able to find an experienced rider with an extra horse that needs riding. 
 Then you could ride with them for awhile to check things out first hand.  
Once you get involved and connected, you can find a plethera of ways to get 
started in the sport.
Good Luck in your quest.
Linda and Buhni