The quality of being splendid or magnificent.
Splendiferousnesses is a very positive word, describing something really great or wonderful.
Examples:
The splendiferousnesses of the fireworks amazed the crowd.
We were all in awe of the splendiferousnesses of the royal palace.
The splendiferousnesses of the sunrise took my breath away.
The splendiferousnesses of the cake made everyone smile.
The splendiferousnesses of the party was beyond anything I had ever seen.
The splendiferousnesses of the waterfall was like magic.