The good thing about xrumer compared to GSA is the fact that it can solve captcha and have big lists integrated by itself.
GSA is probably better for churn'n'burn with good lists, captcha breakers and stuff like that.
You must be kidding, both of them solve captchas! I can tell you even more: they use similar services, like death by captcha or 2captcha.com. The last one is cheaper. GSA has in-built OCR captcha braker as well and it emulates APIs for services.
From my experience Xrumer is slightly quicker, but i like GSA more. First thing you need is a good base.
i have both Xrumer and GSA, compare with GSA, xrumer too much expensive and too difficult to learn. gsa make seo easy. xrumer nowadays old fashion. xrumer lost market because it mainly focus on forum post, but google do not value forum post anymore today. GSA step into web2.0, and xrumer still stay at web1.0
I do not believe xrumer is in any shape or form relevant anymore. Even for a churn and burn, almost 99.9% of those links will do nothing. If I'm mistaken, someone prove me wrong.