Sargatanas is pretty good. It's busy most of the time; the only time it's really hard to make a PF group is between 3-9 am eastern or so. The rest of the time you can put up a party for anything from T1 to Titan EX and have it fill up within 10-15 minutes. It's kind of hard to get onto the server itself because it's restricted from new character creation for a goodly portion of the day; the best time to try to get in is very early in the morning.