Not exactly.
The OP asked for all opinions/experiences. Here's mine (and believe me, I thought long and hard before posting on this thread because I know I will probably be flamed by someone).
We had an unhappy experience on SWA at MCO in May. Got there early. Had "A" passes. Got in the "A" line early. We did everything right. What we didn't count on was there being only 10 people (including us) in the "A" line, 3 people in the "B" line, and 2 people in the "C" line. There was one wheelchair passenger pre-boarded, but all the rest of the passengers on that full flight were families pre-boarding with kids. Thats A LOT of pre-boarders. Our "A" passes were worthless. On top of that, there was a family of 5 ahead of us in the "A" line. They staked their places out waaay early. But I noticed they actually had "B" passes. Did the gate attendant notice? No. They got to board from the front of the "A" line (and yes I mentioned this to the gate attendant, but all he did was yell down the jetway for them to not do it again).
I understand families want to sit together, I truly do. I have children, who are now adults, and flew with them from the time they were babies. I know how much it means to get seats together. On this trip, our family consisted of me and DSis and we would like to sit together, too, and did everything we could to ensure that, to no avail. For us, this system failed abysmally, and it wasn't because we ran up to the gate at the last second.