The 219C has the lowest VF of them all, the Samsung LH351D is next, and the SST-20 has the highest VF.

The SST-20 has the nicest beam with nice throw, LH351D is up next with a very nice beam, but floodier, and there is the 219C which last but not least, with a nice beam still, but some green in the spill.

The LH351D is the most efficient, with the 219C and SST-20 being the same.

Therefore, the best balance of brightness and beam would be the LH351D.

If you want more throw, get the SST-20.

For regulated builds where the concern is just runtime, the 219C would be your best bet.