I have both good and bad experience in groups. Though I've never used the group finder because of my most recent bad experiences.
I was in a group going for the HK pieces. At the beginning of the FP I clearly stated I haven't run either FP ever. I stated so because I view that as the common courtesy to everyone else so then they know I have no clue and hopefully have at least a sliver more patience with me. Now one player was great. He (or she) told us to follow him /her and then to wait before starting the one fight. Explained completely what to do. All was good. Apologized for any mistakes I made along the way. All was fine. We were doing Foundry in Hard mode. Got to the Revan fight, and another player who also stated they'd never run the FP ended up swearing at me. I was swore at for not healing him/her with a move that has a 5 minute cool down and was just used to revive another member of the group. After that this player wouldn't stop with the elitist type attitude. The other person however seen what we were doing wrong and instructed us on how to correct it. We did, and ended up finishing the FP with ease after that.
I've had other negative experiences. But this one was the reminder for why I just don't bother trying to do Flashpoints and heroics. Yes, I am willing to look up videos to see how to do things, and I do try my best while in group play & am willing to listen to advice or polite instruction for improvement or correction. But I don't play the game to be subjected to the arrogant attitudes and abuse. My solution is to bypass the heroics and flashpoints.