As a prospective D50 buyer, I'm weighing up 18-55 vs 18-70. Never used either but have the following comments following various sample images & reviews other than the obvioius coverage/aperture/build/weight/price:
Appears to have less distortion at wide end and less vignetting.
Takes smaller / more affordable filters.
Appears to have less chromatic aberration.
Non-rotating front for filters
Has a proper manual focus ring.
Indication of focus distance.
Cost (£100 more for 18-70 as part of kit) is real issue to me but it's this last that has me stumped. Could I put up with a lens where it's impossible to set the hyperfocal distance for big DOF. But then, maybe I can put up with the 18-55 until I can afford a lens that's better than either and getting rid of it won't have lost me so many £s. But then again, the 18-70 is a more verasatile one-lens solution (I'm definitely not interested in the 2-lens kit). As you can see, I'm still wavering.
PS I was a bit confused by Ken Rockwell's review - it didn't really say why he thought the 18-55 was better. Any help would be appreciated re my reaching a decison.