Wanderer wrote:
I'm looking to buy a Dremel or similar. Any recommendations please? Are
the budget/cheapie versions comparable with the top-end? How much

No.

vibration is there when using these? I'm thinking of using it to clean
up soft-fired greenware (porcelain that ain't fully fired so is still
reasonably workable, but fairly fragile). I'm just wondering if they do
produce too much vibration, the SFGW might shatter, or pieces splinter
away.

http://www.tooled-up.com/ (IIRC) do the basic dremel plus
a couple of basic bits for 34 quid or so.

Vibration of the workpiece isn't really much of an issue.
I suspect that what you want is solid carbide burrs.

I bought a couple of these at 6 quid or so each.