The way the Marquis jet card works for NetJets is this:

You purchase a set number of occupied flight hours for a fixed price. I think for our smallest aircraft (the Beechjet/Hawker 400), the price is around $120,000 for 25 hours. This is 25 hours of occupied time. You won't have to pay for any reposition flights and you can fly wherever and whenever you want within the capabilities of the aircraft and with a certain amount of notice (somewhere around 12 hours I think). I think you have 12 months to use the flight time.

The pros include a relatively short commitment period and low upfront capital expense (compared to fractional ownership). The cons include the fact that you don't get any of the "ownership" benefits such as the tax breaks and you end up paying slightly more per flight hour than if you owned a share of an aircraft and totalled the share purchase price, monthly fee, and hourly fee.

I hope this helps.