Pros
The educational benefits are the reason I joined the Guard and a great reason to join. The other great reason to join is to get your life on track. Basic Training teaches the discipline you need to succeed. The benefit of joining the Guard over the active army however, is that when you get home from your initial entry training you can begin building your life. Not only do you get 100% tuition assistance but the GI Bill pays you $300+ a month to go to school. The money to go to school and the discipline to be successful is a powerful 1-2 combination that sets you up for success.
Cons
Joining the Guard does have its downsides. Basic Training was a pain. Even after basic, days can be long with a lot of 'hurry up and wait'. Being gone twelve months on a deployment may seem like along time. Drill weekend has a bad habit of always falling on the weekend of your second cousin's wedding or some other event you might like to go to (they generally will let you miss drill for important events like your kid's wedding as long as you give notice). Funny thing I've noticed is that when you enlist, drill pay seems pretty good, but joining the Guard generally has positive effects on your civilian career so after a while it may seem like drill pay isn't enough by comparison, even though you wouldn't be making that much if you weren't in the Guard in the first place. Kind of a catch-22.