On the face of it, without knowing all of the details, you have 3 obvious choices, the 60, an Excel or a 800XP. The 60 is the quicker of the 3, but also burns the most amount of fuel if you fly it hard, the Excel has less of a "ramp presence" then the other 2, but is a well proven airframe, especially in Europe and has good residual value and is easy to charter. The Hawker is the heaviest of the 3, cost a bit more to buy, but will carry a greater load on a longer distance. Per seat, the Hawker and 60 are similar in operating cost and the Hawker has better residual value so over time it may actually be the cheaper option. The cabin of the Hawker is the biggest of the 3 and flying 600 hours a year, may well be worth the investment. The only downside of the Hawker is the lack of luggage space, but the 60 isn't that much bigger. Dollar for dollar the Hawker based on 600 hours a year and 4 year ownership will be cheaper then the 60, and you don't have to wait for it to stop raining.....
The 60 does have brake issues and if you decide to put the aircraft on an AOC, contaminated runway data is atrocious, the XR got an extra disc and is a lot better but then you are in Hawker territory again.
You really need to punch all the numbers in a spreadsheet and see what comes out at the end. 400-600 hours a year is definitely the right amount of hours to be thinking about your own plane.
Where are you going to base it and what are the maintenance providers like? At least you are looking at roughly the right size of airframe for 600 hours a year and the operating area you are considering.
If you don't have the exact breakdowns for each type you are considering, get a report from Conklin and deDecker, well worth the money. IF you are serious about putting the aircraft on an AOC, call around to operators that curently use your chosen types and talk with all of them, with the prospect of getting an aircraft on an AOC, they will all bend over backwards and help you out. Also see if you can get a hold of all the AFM's somewhere to get your numbers right.
Lots of questions to answer.