Difference is the older machine takes about 2 minutes to clean a set of blinds (better for commercial) and the newer (shine a blind) around 30 seconds.
The difference in performance may be that the one machine's generator(s) aren't working properly. We purchased an old Shine A Blind machine from another cleaner a few years ago that finally died. When it did we found out that one of the things that hadn't been working was the power level switch or internal electronics. Whether it said hi or low power it had actually been just low power. (Something we'd suspected.)
Comparing ultrasonic machine performance without knowing frequencies, power and other relevant factors including water level and temperatures is very subjective.
Back issues of the Blindcleaners.biz Newsletter have articles (as does the Member's Resource Library) about some of the specs on various companies machines and articles relevent to the science of ultrasonics as it applies to blind cleaning.
The latest newsletter that went out today had things relevant to blind cleaners, but nothing technical. Several of the manufacturers are currently revamping their models and offerings for the industry so there may be some new models of ultrasonic blind cleaners on the market in coming months. Stay tuned.