This salad is about contrasts; of flavors, of textures, colors, and if you are quick enough, you can even work contrasting temperatures into the salad. Escarole and radicchio are both bitter, but the roasted beets with their marination of balsamic vinegar provide a sweet contrast. If you wait to grill the radicchio until just before dressing the salad you can even get a contrast between the hot red radicchio and the rest of the salad which is served cool, or even cold. Radicchio can be quite bitter, but grilling it mitigates much of the bitterness. To step this salad up, check the options in the ingredients. The use of avocado or a creamy blue cheese, or adding romaine lettuce will mitigate the bitter elements further and will contrast nicely with the crunchy elements.