Yes the M! builds do looke like the previos OS. Just like Longhorn looked jsut like XP when those builds first started to leak. It isnt until the Beta Stages that they start to get their own unique look.
mak already answered this.. longhorn (aka vista) looked exactly like xp in beta cause they don't bother with interface upgrades until they've done the inside work. the interface has no priority until everything (most things) are working properly and most if not all the kinks are worked out.