I have tried a few blackberry flavors but not really hit paydirt yet. The TPA version is virtually useless. Capella's is decent but not a true Blackberry in my opinion. I do have FA and MF, but no real experimenting yet save for making a 1% stand alone of the MF one. It was ok but I think it deserves more experimenting before I make an assessment. But I think perhaps the MF is similar to the FA version as they smell quite similar in the bottle. And for that reason I'm thinking that HIC's notes on FA may well translate to the MF one as well. He says...
Less than 1% !! warning, strong flavor!
FlavourArt states this is one of their strongest flavors. 1% standalone is very strong.
The background flavor is musky, like wild blackberries, and earthy. If it tastes like soap or perfume to you, you are using too much. Consider making a 10% dilution to use as your flavoring - this makes it easier to use very small amounts or fine-tune your percentage.
Fresh Cream is excellent to lighten the flavor, and plenty of other, sweeter flavors in a recipe will give the best results.
Fans of berry tobacco might enjoy a tiny (0.1%) touch of Blackberry in the background for the dark berry flavor.
If you have an aversion to floral flavors but want dark berries, consider using FA Forest Mix instead.
Blackberry mellows some with a long steep.
Food for thought although as I said I've got very limited experience with the MF flavor and have yet to mix with the FA one.