I am not very good at reddit so I apologize in advanced! /u/Djgoreface requested a few flavors so here is my opinion.

Flavor west:

Butter Rum- In the bottle it smells identical to the butter rum lifesavers they release during the holidays. Its sweet and buttery with slight rum notes. From my experience a lot of FW flavors can be on the light side so I tried it at 15% first. It is really weak, the taste is good, its just very faint. Even at 20% this flavor is still really light, I tried adding vanillin and a bit of butterscotch and that definitely helped but the butter rum flavor just wasnt as prominent as I was hoping it to be. In the end i made a pretty good butter rum coffee cake, its just too light of a flavor to be used on its own.

Cookie butter- Im not sure what to think about this flavor, it smells like molasses and brown sugar out of the bottle. Almost like a gingerbread cookie without the ginger. I mixed a test batch up at 10% and tried it on my dripper. Its extremely dry tasting, I didn't like it on its own at all. I tried it again with a little bit of vanilla custard, and it still had this strange dry taste, almost like I ate a spoonful of raw cinnamon. Really strange flavor, I never attempted anything else with it, although I plan to use it as a crust for cheesecake or something of that sort. I think it has potential I just haven't figured this one out yet!

Butter cream- This smells like butter and crayons out of the bottle, its not a horrible smell but its not appetizing. I ended up making a pretty decent butter cream pie, this flavor needs to steep for a few days to get the waxy taste out in my opinion. All in all not a bad flavor, can be used to make desserts tastes buttery.

TFA:

Key lime- This is a strong flavor, I use it at 1-4%. This is a true key lime, its not too sweet, slightly tart. Makes an amazing key lime pie and can be a great addition to fruit flavors as well. FW has a key lime that reminds me of crayons and lime zest, this version is much better.

(OP asked for malted milk extra but I havent seen that so I am assuming it is the same flavor) Malted milk concentrate- Very potent flavor, I never use it over 2%. So far I have had awesome luck with this flavor. I use it as a milk base for cereals, milkshakes, and even custard blends. Its very dynamic and can add that extra creaminess that some mixes lack, I find that malted milk and dairy from TFA make a even better milk base when combined.

Kentucky bourbon- This smells and tastes just like Kentucky bourbon, I'm not a fan of drinking alcohol, but it can definitely add something special to any blend. This is another strong flavor, I haven't used it over 2%. So far I've made a jack&coke that's spot on, and a castle long reserve clone that I ended up like much better than the real version. This goes great with tobaccos, custards, and desserts. Its the only alcoholic flavor I have found multiple uses for.

(OP asked for FW dulce de leche but I have not tried that one so Ill review TFA's) Dulce de leche- Awesome flavor, it can help round out dessert blends that are lacking depth. Its slightly sweet and milky on the inhale, and the exhale is similar to a light graham cracker flavor. Makes an amazing custard, and can add a slight bakery note to dessert flavors or coffees. I've only tried FW's version once before, but from what I can remember, TFA's version is much better. I use this flavor at anywhere from 2% as a accent flavor, to 8% as more of a base flavor.

Thanks again to /u/Botboy141 for putting this together! And I noticed you referred to me as a "he", so for future reference I am a girl :)