I belong to the Mountaineers. Took their basic class. Learned the BASICS. Took a year off, almost have finished their intermediate course. During the year off, I did three or four courses with Mountain Madness. I agree, the guides are the pros from Dover, you'll learn more from them. More $, though, and unless you know someone to climb with once the class is finished, then you'll probably lose what you gained.
The advantage to the Mountaineers, and probably the WAC, are the people you meet share common interests as you and you will end up meeting good climbing partners for your future endeavors in the hills.
We all started out incompetent, but gradually have enhanced our skills.
You may want to check into the Tacoma Mountaineers and their basic climbing course. I think they start a bit later than Seattle, and the course is a bit smaller.
Best of luck.