PUG groups are always a crap shoot and I wouldn't recommend you seeking them out for HM/NiM Operation content. That is not to say that I haven't been in PUG groups who have downed the content either. You normally have to find a good group (guild run, etc) and start networking with other players so you can feel comfortable knowing you have a good group.
I would suggest you start looking for a progression guild. Start researching a little bit and find a home, it makes things much easier, even if you aren't on a progression raid team, most guilds I know, including mine run alt runs to help gear others members who don't get the opportunity to raid as often through HM content on the weekends.