DTW-London is about 3250NM Great Circle, probably 3400NM route distance especially if you enter the tracks. That might only be doable going east. Probably not going west with a headwind. London-KTEB wad about as far as I would like to go (3000NM GC). CL300 has less range. Don't know about the Falcon 2000 but heard it might go a bit farther.
The 604 is great and very reliable. Mostly had good experience. Chartered it for about 5500USD/h. Never hangered it