For those undecided as to the Glass or Plastic question...
They both have ups and downs and are best suited for different things however:
If you have kids or small pets that like to jump (or you are accident prone), glass droppers may spill more often (or be subject to same) than a plastic dripper bottle simply due to them being open much more often than the plastic counterparts.
ie if you use platic to drip or transfer, you may spill a drop, if you use a glass dropper bottle to drip or transfer, the entire bottle is uncapped and open, can be knocked over etc.
Granted we need to get the fluids into said containers somehow first, just stating a glass dropper is more accident prone as it would be open more often.