lease for 6 months with option to purchase -
if you do more than 1 RF per week then you will pay machine off within one year or so
but first do what i did
have each rep come with a trial unit and schedule 5-10 RFs in one day - they bring all the probes and all the needles and the machine --- tell them that you liked it a lot but you are trying to decide between their machine and XYZ company...
then rotate through the reps until you find the one you like the most (personally i chose neurotherm)
I basically got about 40 RFs done for free by the time i was ready to sign any paperwork...
if only i could have gotten away with that for the c-arm - but that is another story...