Hi Dilinger,
I changed from Lantus to Levemir at the beginning of the year. The doses have been identical, no perceptible difference in weight ( I'm a couple of pounds lighter, but I don't attribute that to my basal insulin), but hypo awareness has improved slightly.
Bernstein is an advocate of using slower acting insulin for larger low carb meals so that the profile more closely matches the slower release of glucose. I find it works very well for dinner for example, while smaller meals and smaller doses, brekkie and lunch, seem fine with Humalog.
All the best,
fergus