I've played the first game several times now, often because I wanted to try out "the other side" but I always side with the order

I just like Siegfried a lot more than Yaevin. Siegfried is chivalrous, he does not frown at Geralt for being a mutant and he just seems like such a bro. Something that strenghtened my belief in the order was how Siegfried reacts when you save the hostages in the cemetery rather than hunt down the scoia'tael. He's proud of Geralt for having saved the innocents meaning that Siegfried isn't just some bloodthirsty savage out to spill elven blood. His order might have its flaws, quite a lot of them, but Siegfried is a true knight and I always make my Geralt believe that Siegfried can get the order back on track and give it a real purpose again