I've had two serious romantic relationships in my life.
My experience in the first (as dumper) was that I threw myself into another relationship, which ended up being short-lived. I didn't process the breakup or learn/grow in any way.
My more recent experience (as dumpee) has been, surprisingly, immensely gratifying. There have been hard times, but through these I've regained my self-confidence, self-respect, sense of humor/adventure/openness/joy, and I feel tremendously optimistic about the future. I lost 20# from being more active, and I'm making new friends and trying new activities, and am so grateful for how things are turning out for me.
The dumper in this case threw himself into another relationship (shortly before said dumping), and I believe it's been a struggle for him. Time will tell, but it isn't my concern anymore...