I was doing quests in Jharru Flats/Qalia (Turtles by River) and found the experiance very difficult due to chunking issues. There is a chunk zone running roughly parallel to the river just slightly to the east. The turtles would routinely appear to be running back and forth through this chunk zone yet this could either be an optical illusion or not (death or no death). If I pulled one to many and tried to run east through the chunk zone, I sometimes came out behind the turtles and typically stuck for enough time to get whacked in any case. Also, I would approach the turtles invisible with plenty of time left on my invis timer (playing a psionist) and as soon as I went through the chunk zone would always loose my invis.
I realize that there are still issues being worked out, but I would hope that Sigil has chunking high on their list of fixes. Fighting anywhere near a chunk zone is certaily perilous for now due to game issues