MIMF

I am thinking about getting a scroll saw for cutting out thin pieces of work. (yes I know the most people use bandsaws for this). Scroll saws come as fixed speed models and variable speed models. Clearly there are advantages to a variable speed model but the price tag is different. What I am looking at is a fixed speed of 1400 vs variable 400-1400. The former are frequent enough on the used market, the latter are not.

Is 1400 too fast for doing tops, backs and acrylic (plexiglass) sheets for templates?

I had a fixed speed dremel scroll saw and it always melted every piece of plastic I presented to it. It may have been the short throw or the lousy blades that came with it. My bandsaw melts everything too so I don't know if the slower speeds would help at all.

High speed is good for very fine toothed work and hard woods. Slow speed is good for less aggressive cuts in soft wood. If you plan to cut both ebony and spruce (and plastic) I would get the variable speed.