Ok, I am impressed by the way Xrumer handles forums posting. It can also handle blog/comment posting, but nothing special here, GSA works better.
Xrumer pluses:
- amazing speed and accuracy when it comes to forum posting. If you also get Xevil, I think it is the perfect tool for forum posting. A total beast

- proxy/email management is good.
- pretty good support in the first days, even though I heard horror stories about their support.
- reports of successful links are detailed, but I haven't found a way to strip the text comments after each link and get the full urls list with no text around it.
Xrumer minuses:
- huge learning curve for almost all users.
- everything else, really. UX is bad, verifying posted links should be done either by hand, or by using Scrapebox or by reading 100x times the manual.
- lack of direct options to choose anchor text percentage - you can only do it by spintax.
- lack of customization for forum posts, blog post etc - it's one spun piece of content for all.
- prepare yourself to work with a lot of files, like 20 years ago. Everything is retrieved manually from files.
- lack of good documentation. the docs are made by the authors, according to their logic -> it takes a while to understand.
- after 3 months, you need to pay $10 to be able to use the program for 30 days more. It's not recurring.
- last but not least, BE AWARE, it can submit to contact forms here and there, support says it confuses feedback forms with contact forms sometimes, but Xrumer by default will not post in contact forms. From what I see in the logs, it's different. So it's a risk you will take unless you read and ask a lot how to disable this.
Overall, I am not going to dismiss Xrumer, in fact, I am going to run full campaigns through it and see the final results. Unfortunately, the best thing to do after a blast is to wait a while and check backlinks with Ahrefs, their system of checking verified links is beyond my understanding, in terms of logic and usability.
In the end, GSA SER is far better, but Xrumer might be good for some types of blasting which still works with some search engines.