I have travelled couple of times on shalimar and also on business!!! if you ask me i love both...in shalimar you can get to see all beauty of land plus if you are travelling in AC Parlour while if you want a relax over-night journey where you want rest too, go for business express!!!
As far as timing are concerned, shalimar been upto timetable where-as business is always on spot....Actually shalimar timetable is tight, if due to any else fault train has to stop or make delay, it cant cover that lost time due to the factor that it has to stop in between but also has to cover distance in 18 hours same time of business but with many stops!!!
Thus, both service is good...if you ask me, If i am tired and want peaceful journey then I will opt for businees but if I want to do some Pakistan landscape spotting then shalimar!!!