i pretty all of easy-hardest (and most of Inferno) with the WD using only the lances, so i'd say they're pretty good! but it depends on how you play the class - i'm a fly into the fight guy, and then kite them around the level. i want something that i can point at an enemy and know it's going to die, and still lets me have the energy to fly to the next.
the fusion blasters are GREAT for the ranger, if you know exactly what you're using them for. eg, for something you want to do a lot of damage to in a short amount of time (eg quadruped fortress hatch, waterside bugs nests), they're your option. that said, i've found that for inferno the best fusion blaster isn't strong enough to take down much more than 1 nest (at least, online with the 4 player multiplier), so maybe the dream is over.