Can't speak for Euro-traveller on GB - but the CLub Europe service is at least equal - but usually better than that on mainline.
The seating is the same - 2x3 convertibles. Differences are that they serve champagne out of proper bottles, and the crew just seem more attentive. I've never seen a club cabin on GB more that 3 rows (and actually went on a flight with only 1 row of CE - so feels nice and exclusive.