Parmandur
Book-Friend
With the damage type versatility, seems pretty good.For a bit more data. If we look at the higher levels of sorc burst, here is what it looks like (I used a computer sim for this rather than theory so it may be sliiiiightly off)
4d8 sorc burst
Infinite Reroll: 20.585
Max 5 Reroll: 20.547
Standard 4d8: 18
Standard 4d10: 22
so ~2.5-2.6 more damage than a standard d8 cantrip at that level, -1.5 from a d10 cantrip.