How much experience do you have?
What are you currently flying?
What market are you aiming at?
Are you flexible in where you work?
The Hawker 800, best place is probably FSI at Farnborough, although, I doubt they'll be the cheapest. Other places CAE Emirates, Dubai (XP only, sim may not exist any more), FSI Wichita and Wilmington. They're the ones I know of and have used.
Legacy, I don't know much about.
Colleagues who have been Excel rated seemed to have picked up work.
If you have a new CPL/IR and are looking to "buy a rating and see what happens" then save your money. Type ratings on a biz jet cost roughly the same as a type rating on a "normal" airliner.