I used a Spectrum a few years ago - a good few years ago, like 1993. I owned a Picasso II+ from 1995/96 until last year (feb '05). Personally, I preferred the Picasso. Spectrum was nice, but EGS was S-L-O-W. As in very.
If Picasso96 has drivers for the Spectrum, try it and see how it compares to the Picasso. But be warned, if you are used to a PC, they are both slow in comparison; its "fun" watching a screen redraw itself.
As an aside, a Spectrum 110 was nice, this attached directly to one of the GVP accelerator cards, and was pretty damm fast in operation as it cut out the ZorroII bus.