CAP
The CAP is an excellent organization overall with a great mission and a rich history, but the mediocrity you might see is on the unit level.
We had a great wing in Oklahoma and an excellent squadron in OKC. There were politics, but overall our wing was run very professionally. I joined CAP because I wanted to fly, but as I became more involved with it I became more immersed in it. I enjoyed the fellowship. I got a great deal out of the leadership and personal development courses I had to take. Oklahoma Wing offered some fantastic flight training opportunities and I jumped on every one of them. The best example was the check pilot training course. A Monroney Center fed (and great guy) who trains DEs gave us check pilots the same training as he gave examiners. I was eventually appointed as an Assistant Chief Check Pilot and helped put on the course. The experience helped me then when I gave annual Form 5 rides and helped me as a flight instructor, but it was priceless a couple of years later when I was promoted to stage check pilot at Riddle. I had learned how to conduct a practical and therefore knew how to conduct a stage check.
I saw what MBA was talking about when I joined Arizona Wing CAP. It seemed as if the wing commander's wife was running the show. Our squadron was not run professionally at all. I became less active and eventually went inactive.
I attended a couple of meetings at a cadet squadron at Colorado Wing CAP. My impression was that Colorado Wing is extremely political and pilots who want to fly and contribute would have to wait years for the opportunity. Perhaps it is because Colorado Wing CAP is the de facto state SAR organization and receives state funding.
CAP members wear uniforms, with some members feeling the need to do so, but it is nothing like the Guard. You have to wear a uniform when flying CAP corporate aircraft and/or on CAP missions. I didn't mind it. You take initial and annual Form 5 check rides and a Form 5 in each type aircraft you will fly. A Form 5 ride is basically a very thorough BFR-type checkout to Private Pilot standards. Your check pilot will likely sign you off for a BFR afterwards. CAP members can fly corporate aircraft for proficency. There are some flight release requirements. You can instruct in CAP aircraft but you CANNOT charge for your time.
Check out CAP, but, sadly, I must second Avbug's comments in the last sentence of the last paragraph in his post.