I think you did quite well. The difference between business class and coach intra Europe is minimal. If you are lucky the seat is a tiny bit bigger and the food in on china instead of plastic. In most cases, all you get is a free newspaper.

A few weeks ago I was flying from JFK to DUB in coach. The entire flight was oversold (coach and business) and I would up taking an $800 travel voucher and flew from JFK to Manchester to Dublin. I arrived 3 hours later then originally planned in Dublin, and it was early Sunday morning. I also managed to get a business class seat on the flight to Manchester and a business class fare so I earned the mileage bonus.

I think all in all you did well. This was the first time I voluntarily upgraded, and would probably do it again so long as it was a re-route and not a stop-over, although on a weekend I would consider lots of options for $800 to 1000.