Horizontal radio button option groups are hard to read and look bad because the spacing between the options is less than the spacing between the button and the text. Also the vertical alignment to the label is bad. See attached images.

To do:
Make the spacing between radio option group items greater.
Align the options with the label.
Ensure the changes work under these circumstances:

• Vertical and horizontal aligned option groups.
• Radio buttons and checkboxes.
• Looks good on these fields: OptionGroup, Switchable, Checkbox

Tip:
In some quick experiments, this achieved the nice look in the screenshot. But not sure if this works across all the circumstances outlined above.

.v-radiobutton

.v-select-optiongroup