Hi,
There is very little difference in effectiveness between Malarone and doxycycline. The vast majority of people experience no side effects with either drug, but side effects with Malarone are slightly more common than with doxy.
According to the medical experts the potential photo-sensitivity side effect of doxy is rare, my own experience is in line with this, I have known many people who have used doxy (I've used it myself for periods of up to 6 months at a time) and I have only known one person have this reaction.
It is not related to skin colour or tanning / burning it is more like an allergic reaction to sunlight (phototoxicity) resulting in a rash of small blisters.
Some studies show the risk to be dose dependent, the higher the dose of doxy the higher the chance of phototoxic rash. The dosage for malaria prophylaxis is much lower than the dosage for many of the other treatments that doxy is prescribed for.
As said above doxy has the added bonus of also being a treatment for stomach bugs. One significant difference is that you have to continue the treatment for 28 days after your holiday.
Side effects are also fairly rare with malarone, some people complain about upset stomachs, my personal view is that upset stomachs are more likely caused by other things such as heat, alcohol, change of diet both quantity and content, recreational water illness, etc but people blame the ant-malarial.
Both treatments should be taken with food, with Malarone it is best taken with dairy food so breakfast is a good time. If you are taking doxy take it with or after food and make sure you take it while standing or sitting upright and don't lie down in the minutes after taking it. (this is because it can cause heartburn if it dissolves in the oesophagus rather than the stomach)