i love my 200 EXC sm. I would say the 250 is going to blow away the 400.....but the DRZ is a lot more reliable and ment for the street. I guess it all comes down to how your going to ride it, how far at a time, and if you dont mind doing topend kits (in the KTM) every once and a while depending how much you ride.
Never owned a DRZ, but I have a 250EXC and spent plenty of time on my buddies Tagged DRZ-E. Not even in the same ballpark. The E is way lighter than the SM, but still a pig compared to the EXC. However, the EXC has a very hard ride, and it's lack of weight can make it a very nervous machine when ridden hard.
For a daily commuter: DRZ
For an occasional commuter, weekend racer, gap-run bike: EXC