Admiral Nelson: Smooth upon entry to the mouth, creamy, a little thinner than the others. The finish is harsh, almost like you have just swallowed straight dry rum.
Bacardi Oakheart: Entry is smooth and sweet all the way to the finish. This is the sweetest of these rums. A particular creaminess appears in this one and you can pick up cinnamon and vanilla so it has a pretty round taste, it reminded me of drinking a sweet & creamy latte.
Captain Morgan: sweet and smooth upon entry and all the way to the finish. It is creamy, the flavor that most appears is vanilla. Very easy to drink.
Sailor Jerry: Smooth going in, the strength of the rum shows up in your mouth & stays through the finish, but not as harsh as Admiral Nelson. Sailor Jerry is sweet, but it has much less of the cream & vanilla tastes of the others; it is more fruity. What stood out to me the most was cherry. It reminded me of a Dr. Pepper.
Mixing any of these with cola seems ridiculous to me, since they are already sweet & would almost disappear in the caramel flavors & sweetness of the cola (unless you don’t like rum, but you want to drink it anyway), but that seems to be the most popular mixer. I recommend spiced rum in a mojito because I had it once at a bar on Sanibel Island & it was great. I have mixed spiced rum with lime juice (which I like because the acid & sourness of the lime cuts the rum’s sweetness) and pineapple juice (which didn’t make a great drink, but it was plenty sweet).