I have been very happy with them for several years. When it's time to renew, they email. I pay. Then I don't hear from them until it's time again.
Previously, we used Network Solutions. They were TERRIBLE, but were also the only game in town at the time. They have since improved.
Our old ISP was just below the World Trade Centers, and was crushed. The contact email was through another machine at that same ISP. Netsol really gave us a hard time switching, because the email addresses were all down. (I'll never put all the emails on the same ISP again) It took a few days for them to re-point us to the new place. (no one was killed at the ISP, fortunately. Broken bones and major damage to the building. Theyre back in full operation now)
You'll find gripe sites for just about any company or product. I'm surprised there isnt a grumbler grumble dot com j/k
There is also the question if you are just comparing domain registration (which we are here) or registration PLUS webhosting. I have no experience with their webhosting services or packages.
The real nightmare was registerfly.com which is barely hanging on and had a recent drama which caused many people to lose their domains. A warning was posted on the Grumble, so people could get out in time. Many folks are still trying to get their domains back, months later
The problem was mismanagement, and was supposedly because of a lover's quarrel between the two guys who owned the company.
Now if you want to debate bad service, you should be talking about webhosting companies and not domain registrars

There are some nightmares out there.
Best regards,
Mike