The only thing nowadays is the fact that LiFe and LiPo cells are available and much easier and better to use than NiMH cells or even NiCd cells are, though they require a special charger being the main caveat. A person can get two LiFe cells (3.3v each) instead of five NiMH cells and end up with a pack that is much smaller, lasts longer, charges faster, and can be discharged at a higher rate. LiFe cells don't come with the same fire hazards that LiPo cells do, although most receivers today could handle a 2-cell LiPo fine if you so choose.