It quite clearly wasn't. In fact Poland was economically far behind her Western neighbours during that period.
after swedish deluge, about, 1655 the economy of Poland rapidly shrank but still was doing much better than during partiotions(the towns for example were developing the same they were in the West), there were also measures taken in beetween partitions to bust the economy- that would probably work if Poland would live any longer.The education was excellent, the cultural life was busting
in 1920 Poland however was the poorest country in Europe(I guess except for Spain), the towns, the villages, the roads were underdeveloped, high illiteracy, even szlachta(with some exceptions)was poor, the industry was almost non existent etc etc
I am sorry but I fail to see the advantages
P.S. if You are interested I can post You a data(in polish)about the economy of Poland since XIV century, or can try to translate for You some bits, or better maybe google translator- because I dont feel I would do it right