Yeah I remember those speccys, released back in Sept '87 IIRC.
A mate had one, which as you say used those indestructable 3inch floppies from Amstrad that no-one else used.
Despite a radical overhaul of the motherboard, we were still left with the awful Speccy graphics and tinny AY sound chip, a C64 beater it wasn't....
Around the same time, my mate bought a +2 and an expansion port which connected to a 3.5" floppy familiar to us today. With 720Kb it was twice the capacity of the 3 inch drives and was quite a nice machine.
The EuroPC reminds me of the Sinclair PC200, which was basically a PC clone in an Amiga 500/Atari ST alike box. Awful machine...
The other one which sprang to mind was the Miles Gordon Technology Sam Coupe, which was speccy compatible. It too featured 3.5 inch drives, with space for two drives slotted in the front of the machine. I never used one, but it was everything that the Speccy +3 should have been from what I've heard of it.