about to buy used f70

I am going to buy a used f70 and was wondering if there was something I should look at and if one f70 is better than another one. I have a f70 and have had it for 4 years now and have been satisified. I have also heard that there are diff f75s. Is there a differance in the program on the machine from one version to the next of the same model? Help NASA tom!!

Except for very minute' differences............ they are all the same. Upon receipt, you may want to verify air-test depth on a clad dime and a nickel. Play with the settings........... but you should find 'sl' mode to be the best............... and should give you nearly 12" on these coins (with the 11" DD coil).

Thanks for the info Tom!