For me the definition of a powered suit is as follows:
"A suit worn by the pilot that enhances his fighting/survival capabilities, normall not taller than 4 metres. "
Which will would even exclude Votoms as the pilots sits in a cockpit and does not wear the suit itself.
Crusher Joe, Southern Cross, Mospeada, etc have suits that fit the bill and were also released as plastic models. Of course SF3D fits also, but I would exclude things like the HAFS Jerry and similar.
Huge human piloted robots like Patlabor, Dunbine, Mobile suits, etc IMO don't fit the bill.
Most of the powered armour kits I have seen seem to be either 1/20, 1/12 or 1/6 scale, whereas the Robots seem to on average 12 metres and taller and thus modeled in 1/72, 1/100 or 1/44..
But lets hear what the other guys have to say on the topic.