I was gonna write out a fancy math equation that explains how most people decide on what is OP or not, but realized I don't remember how to show that a number is meant to be negative without using a minus before it, which doesn't really work when using words. Basically is the cost, but the number here is meant to be calulated by how little it uses and thus how cheap something is, multiplied by what it does, multiplied by number of alternate options for this sort of object. So if the cost is small, and the effect is massive, yet it is the only thing that does this, the resulting number is 0, but if any other options exist, the equation does not result in a zero as one can compare it to things and thus decide how balanced it is relative to other options.
The real issue is that this would work very well if "what it does" could be easily assigned a number; which it can't be easily assigned as while this is clear, how useful the feature is can change wildly in opinions and even situations.
For Example, Using TE3 Itemducts for Apiaries. One can pull things out and send them down different paths if you install a servo thingy. This means one can bypass the need for a apiarist pipe if one uses workhorse bees(aka genetically sterile and basically clones of each other). So in this case, using the apiarist pipe may seem dumb as the bees can be easily sent into the apiary again and bee goodies sent elsewhere, but they are somewhat expensive(a diamond pipe plus some propolis, which isn't all that easy to get, though squeezing honey drops occasionally nets some(and honey drops are easy to get, eh?)), and itemducts somewhat cheap... so in this example one could say that itemducts are OP. But outside of this situation? They are not too expensive or that much better then your other options(except they cause less lag if used correctly), so they are comparable to your other options and perhaps could be used for a baseline for this sort of thing.
But a great example I wish to bring up: Dartcraft Tools(not rods/tools/weapons, nor the force mitt, tools). While it's true one can easily use DC to get a tool that automatically smelts logs and cuts down whole trees, making charcoal farms easy to use, this costs XP, liquid force, and MJ. Or one could make such a thing with TiC, where it costs a lava gem thingy and requires you to use a lumber axe.
The DC Tool will break easier then if you had not upgraded it, the TiC tool wears out no faster. The DC Tool will break when it runs out of durability, leaving you a force shard as a parting gift, the TiC Tool breaks leaving a broken tool that can be fixed by adding some of the tool head material. DC Tools technically can get repaired automatically by using liquid force in it to repair it, or by using a TC Crystal Cluster. TiC does this with a patch of moss or ignores it with a energy source.
So why is DC OP yet TiC Well Balanced? Because actual balance is just a matter of opinion, no matter what, and this is universally true for things that are called "OP" or "UP".
