I have traveled from Pak Business Express most recently in last week of February 2013 (about 3 months ago). I traveled on Smart class (Fare 3000) and it was great experience as always. The train left on exact time from Lahore and reached Karachi almost half hour before its arrival time.
Now a days they have again started Smart class promotional fare of Rs 3000.
Different fares are:
Economy class: 2500 (No AC)
Smart Class: Promotion: 3000 Usual: 3500 (AC, 10 kg weight limit extra 10Rs per kg, Charging points, No LCD, No Wifi internet, No Food)
Budget Class: 4000 (AC, 25 kg weight limit extra 10Rs per kg, Charging points, LCD, No wifi internet, No Food)
Business Class: 5000 (AC, 25 kg weight limit extra 10 Rs per kg, Charging points, LCD, wifi internet, Food - Dinner & Breakfast)
Btw, there is third option too (i.e. Night Coach Express) which is privately run under Shalimar Group. Departure time 6 pm and arrival time 12 pm (18 hour journey, same as Shalimar, just other way around with timing). It is also maintaining time well but no comparison with Pak Business Express.