Being worlds apart, one would think it is impossible for proponents of Conditional and Eternal Security to find any common ground. One side believes you can lose salvation, the other side believes you can't. It's the law of excluded middle; you can't have both, and unless you're an atheist who believes you can't be saved at all, you can't have neither. But the common ground is not with the premise that salvation can or can't be lost. Rather, it is with the method and end result.
Of course, there are extreme ends of both views. False gospels exist. On the Conditional side, there are "gospels" which state salvation can be lost because of works. This, however, is plainly heretical. On the Eternal Security side, you have spiritual anarchists, who believe salvation cannot be lost not because it is maintained by faith, but because God doesn't care about sin at all. This, likewise, is plainly heretical.
But most believers in both sides can unite on the same Gospel, believing we are saved by grace, through faith, as the gift of God, not of works. This is great, because Ephesians 2:8-10 clearly tells us that this is, indeed, how we are saved. However, if salvation is by faith alone, there is one feasible way to lose salvation: To also lose faith.
As long as we agree on the method of salvation, we can also agree on the end result: Those who have faith at the time they die and face judgement will be saved. Those who do not have faith at the time they die and face judgement will not be saved. If these two statements can be affirmed, then the only real dispute becomes Perseverance. Conditional Security would suggest those who lost their faith lost their salvation with it, whereas Eternal Security, with the added boost of Perseverance, would suggest that if they had faith, they would not have lost it.
This is an interesting discussion to have, but at the end of the day it is trivial. It is vital to stick to the Gospel, and so we can dismiss some versions of both sides as being utterly heretical. But while it seems only logical to insist that we stick to what scripture plainly teaches us, it also seems unnecessarily divisive to criticise those who start and finish at the same place for taking a bumpier road. As far as Conditional Security does not conflict with the Gospel, those who profess it can be considered Christians, if slightly in error.