Newer equipment is generally better. Newer machines have digital readouts instead of gauges with arrows, and many newer machines offer different modalities. I feel blend is generally safer and more effective, but a highly experienced electrologist can get as good a result with thermolysis.
Practitioner skill is most important, but once you find out the name of the machine, you can check most manuacturers on hairfacts.
http://www.hairfacts.com/mfrs.htmlThe main reason I recommend you ask what kind of equipment is to ensure they are a legit business and not using a scam device that is supposed to sound like a legit one. Electrolysis requires that a hair-thin metal filament be inserted into the follicle.
Hope that helps, and good luck!