The simple answer is yes you can use it on your mod, as long as it's not a hybrid top cap, but you probably won't like the results.
The Subtank is meant to be used with a top cap of mod or regulated device that has a positive pin...if you try and use that tank with a hybrid connection style top cap on a mech mod it will more than likely short the battery and bad things will happen.
The reason why you don't want to use it on a mech is because of the lack of options. A mech will fire true to ohm's law minus the voltage drop and you will only get whatever the battery has left of it's charge. With a regulated device you can adjust your wattage to taste...with a mech you have to build a coil with a different resistance to get a different wattage.
The reason why the last poster said the RBA deck would be alright is for that reason, so you can build the coil to your desired result but if you're ok with the OCC coils putting out whatever they'll put out with whatever amount of power left in your battery than to try wouldn't hurt anything. You can also rebuild the OCC coils to a different resistance as well if you like their performance better than you get with the RDA deck...that's what I do. I gave my RDA deck to a friend that broke his and just rebuild my OCC coils to my liking.
Happy vaping and cheers