I have been told that the cuts of meat there and styles of serving are somewhat different to what we might expect here in Australia, the US or UK. What should we try ? I am not sure if I can overcome the psycological stigma of eating the bulls testicles, but any educational comments would be greatly appreciated ?

TTT - Please ?

Very similar from what you might expect in the US.

Try Rib eye (Ojo de Bife)or a Bife (Baby Beef)

Be aware of the term of your steak, in my opinion argentineans tend to grill their beef for longer periods.
Keep away from the Achuras plate, wich includes testicles and other organs.

My two favorite cuts:

Bife de Chorizo (sirloin) and Lomo (Tenderloin).

Most menus will have these items listed seperately, along with something called a "parrillada" or simply "asado"....If you order this item you will receive morsels of many things....chorizo sausage (excellent), pollo (chicken), and various beef parts, including costillas (ribs)....but watch out for morcilla (sweetbreads), rinones (kidneys) and morcilla (blood sausage). I have only seen bulls testicles listed on two menus in Buenos Aires...but you never know.....

Bien Cocida...well done
A punto...medium
Jugoso....rare.

Thank you all for your help. We have 5 nights and I have made one dinner reservation reservation so far at Cabana de Las Lilas. I will make one more dinner reservation and then figure the rest out by visiting when we get there in mid to late August.

I am sure you will enjoy Cabanas de las Lilas. Service is excellent, great ambiamce, food is excellent and very nice people around. It is not the typical argentinian restaurant, due mainly to cost. Make sure you order some empanadas
Buen viaje...