** No Spoiler **
Quite enjoyable. They do a good job with this prequal, tying everything in with the first two films. Rhona Mitra worked out as Sonja and the nice thing about it is that she doesn't have to directly compete with Kate Beckinsale since they're playing different characters unlike Maria Bello vs Rachel Weisz from the Mummy series (I pick Weisz because I loved the Weisz vs Patricia Velasquez fight in Mummy Returns). Indirectly, I think Mitra is a bit more physical than Beckinsale.
If you enjoyed the first two films you will probably enjoy this one.
Looking forward to the next one.