Silver puppy has been my choice for years, but have had only one other and that was, Bob Becks which was also a zapper, so I can't comment on the others you mention.
The SP is compact, but with the latest electronics that allow either automatic, or your choice of settings in case you want a stronger PPM. The others might too, I don't know. I have had years of trouble free service with my SP
I would suggest a stirrer like the one pictured regardless of which one you buy