Anybody have advice about HMOs?

My spouse and I live in the Sacramento area and are trying to chose between two HMOs offered by my work. Theres also a PPO option but we've kind of ruled that out. The two HMOs offered are Kaiser and Cigna. We just graduated from college so we're kind of lost. Anybody have any advice or experience with either of these??? Also if anyone uses either of these, are there any doctors you recommend?