Will doesn't eat NEARLY as often. Kalena would have nursed all day every day if I let her. (And some days she came close.) She also took a pacifier pretty much any time she wasn't nursing. Will generally eats every 2 or 3 hours although he usually cluster feeds at some point during the day, eating every hour or so. He will take a pacifier, but doesn't need one.
Will is also a MUCH better sleeper than Kalena. Kalena pretty much only slept in the sling or if I nursed her. And at night she would sometimes be up for hours at a time. Will does pretty well at night, although he doesn't usually settle down for the night until 10:30 or 11:00 pm. During the day he'll sleep in the bouncer or sometimes just laying on the bed. (Usually the bouncer because it's much more convenient.)
He hates having his diaper changed, but he also HATES having a wet or dirty diaper so no point in putting off the changing. Kalena didn't seem to mind the dirty diapers so much.
One of the biggest differences is how aware Kalena was at 4 weeks. When she was that old most of the comments we got (besides the ones about how much she looks like Brian) were about how alert she was. (That was probably because she NEVER slept.) By 4 weeks she was smiling in response to people (specifically my dad and my sister in law Amy-- they could get her to smile every time they talked to her); Will has only had gas smiles. Also, she had already laughed at 4 weeks! Crazy. Definitely no laughing here yet.
I'm looking forward to seeing how different or similar they are as they get older.