They seem to have some ongoing issues with their client - there have been speed issues with the last couple of releases, on Windows at least.

I've had to regress to an earlier version or I get DNS timeouts galore with v60. There's quite a few open threads on their forums about this.

Aside from that, their IPs seem to regularly get hit with Cloudflare captcha. Usually, but not always, switching to a different exit will fix, for a while at least.

I've not found anyone better though.