Good old strawberry has caught me loads. Put the flavour into the bag, the put your cubes in- give it shake and stick it in the freezer. The process of freezing and thawing out draws the flavour into the meat more.
Hold on a minute there chaps...synthetic flavours on a base mix have caught probably 10 fish for every one without.
I'm not saying that the base mix shouldn't be over looked...on the contrary...it is the most important long term part of the 'boilie jigsaw'.
But to use an analogy...when I've had a pint or two I'll eat ready salted crisps and enjoy them (if you'll accept ready salted as 'unflavoured' for the sake of the analogy).... But other days I'll fancy salt and vinegar, cheese and onion etc etc.
They're all the same...but with a synthetic flavour over the top.