I had a chance to fly the Angel with the Hacker A50 12L (over the 14L I purchased which I feel doen't provide enough RPM's) and it flys great! I got 8 flights on it last Wednesday and the additional RPM's really make the difference. I guess in the end if you use the recommended packs (3700's), then stick with the A50 16S but if you have larger capacity (i.e. more amperage) packs, go with the 12L...

Jack