As a *Gold you are allowed 40kg - JK is full member of the Star Alliance so they will give you the 20kg extra baggage allowance too.
Spanair will indeed not be on a top position on the "best airline of Europe" list - but it is not that bad. IŽve been on much worse aircrafts.....
At least the business class service is good, domestic as well as international. Service in economy is of course simple: nothing. But their competetors in Spain are for sure not better. If you can manage to secure a seat on an Air Nostrum flight (regional subsidiary of IBERIA) youŽll receive very good service - every other airline (Air Europa, IBERIA, Clickair....) provides a servicelevel as simple as Spanair.