So far it's been a positive experience for me. We've communicated for a while and my project was a big one and they've stuck with it and that has been a big positive for their credibility concerning the service they offer connected to this thread.
Concerning speed of the service, I was informed that slow was the best way to get the links placed to protect the site and I deferred to their wisdom. From what I can see, it has worked out. You need a provider that understands the importance of protecting your project and doesn't get your site banned. I can only speak to my personal experience and "at this time" I have no reservations recommending them to anyone.
In full transparency, the only thing I believe could be improved (again speaking from my experience so far) concerning this service is in regards to the updates. I typically reach out to them to get an update and when you're paying for a premium service they should be reaching out first. Maybe I'm old school like that but that's my perspective on it. However, when I do reach out, they do respond and we determine a timeline on when I will receive the next update.
Overall, my experience has been good and if I were to need Wikipedia links in the future, based on what I have seen personally on my project they are working on, I would order from them again for other projects in the future.
I hope that helps you determine whether you'd like to proceed with them or not.
Note: These are my thoughts alone and are not sponsored in any way for any compensation or gift from the team.