Any suggestions on a good electronic chess set (mid-90's or earlier)

I have the radio shack 1650 endorsed by kasperov. It's one of the smaller ones that I got while in college. It is very hard to win a game even on lower levels and it actually made me a worse chess player, I think because of being able to take back moves in an attempt to win. I much prefer playing here, one day games, than computers.
Hey guys,
I'm looking for an electronic chess set. I prefer the older electronic sets. It must be difficult to play (or even impossible to beat for the average player).
I've just got my son one off Amazon, but it's purely for learning. He's 8 and loves chess.
But I'd like one for myself. I've fond the following:
Saitek Team-Mate
They're all within a decent price range for older units. I have about 50 (GBP) to spend.
Any advice much appreciated.