Just had a look at this in September 1983, and it is still valid today (we are in February 1984, game time) so I want to share the results with you.
Below is a comparison between the 727 and the 320 on operational lease for eight years. Similar seating, standard business and economy seats.
old Boeing 727-200Adv VS new Airbus A320-100; game DofM #6, September 1983
B- December 1983
A- April 1988 (almost 4 and half years later than boeing!)
Availability in the used market
A- None, new airplane
B- order 1 834 million USD, monthly 314 000 USD
A- order 2 793 million USD, monthly 465 000 USD (52% and 48% higher!)
B- Y150 C10
A- Y138 C10 (8% less economy seats!)
B- 2000 NM
A- 1500 NM (25% less range!)
B- 4 100 kg / hr
A- 2 660 kg / hr (well done Airbus)
B- A check 6 168 USD * 130.05 = 802 148 USD
A- A check 3 078 USD * 130.05 = 400 294 USD (very good Mr Airbus!)
The lease savings (151 000 USD * 12 = 1 812 000 USD per year) on Boeing exceed the maintenance savings (401 854 USD per year) on Airbus by over 1.4m USD per year. There is also close to 1m savings one time only upon order. The capacity is higher on Boeing, with 12 extra economy seats. The range is also 500 NM higher on Boeing. The only bad point for Boeing is the fuel consumption, which is 54% more expensive.
My two cents
I prefer the old Boeing. It gives me extra seats, extra range, extra savings, and it gets delivered this year (I start making money now) as opposed to several years later. If I need more there are many available in the used market. All that covers the extra fuel cost.