I find them much easier to get into with the Group Finder than they used to be, but there still seems to be this weird gap. What I mean by that is from 10-30 it's really easy to get FP pops, but from 30-49 it's like they disappear and people don't do those later ones.
When I was leveling my Gunslinger, I could get into CWG and MP without much waiting, but once I hit around 45/46 and started to having to do Red Reaper or D7, it was horrible. Most of the time any 50's that were grouped either declined or quit group afterwards (I'm not sure why, RR isn't that hard if everyone takes a moment to figure it out).
If you're trying to do a low level FP with the GF and there are no takers (Hammer Station/Athiss) it is a good idea to go planetside and ask people to queue up because sometimes new players don't know how to use the GF or even know it is there and sometimes people just need a little nudge to click on it. (Now that they have added the 'return to previous spot, it will probably/hopefully get more players to use it while leveling without the worry of having to go to the fleet again and lose their place.)