I guess that in the UK, many of us cut our teeth as kids with an unexpanded shell because they were cheaper; normally an old 1d (older, large penny) or a decimal 2p. As neither are milled-edged coins, the inserts look fine. It just made it more difficult to keep track of the reduced diameter coin during performance.

I think the first expanded shell that I saw was in the mid 1980's - it was a U.S. half dollar. Unfortunately, it was very shallow and often slid off the coin it was covering - I wonder whether this is where the initial concept for a Slippery Sam gimmick was generated?

I used to use expanded and non-expanded shells until last Summer. That's when I discovered the Tango T.U.C. and my range of shells went onto ebaY.

For me anyway, the T.U.C. does EVERYTHING that any shell can do - and a whole lot more (given, for example, it's magnetic properties). It's also much easier to handle (with practice), doesn't 'talk' as much as a shell and can be subjected to cleaner handling; e.g. easily thrown around, shown on both sides, etc.