It's a decent cash farm, although with Cata dailies x4 or x5 even that isn't so good anymore. The gold drops from bosses were nerfed but they still drop around 40-50 gold each and you can run right past most of the trash (or, if it aggros, you can flatten them very quickly). I did it the other day in around 50 minutes or so and I could probably cut that down by a good 10 minutes or more.

But I agree that it's not worthwhile for the legendary weapon (go farm Illidan/Kil'Jaeden, IMO) or for gearing up alts. The item level of MC drops is 66-78. The item level of quest rewards in Hellfire Peninsula is 81-93. It's been a while, but I can still remember how crazy it was when I got into the BC beta and saw how fast gear was made obsolete.