Don't want this to come across as a bitter ex-subscriber - but I had this service as my back up for nearly a year, so think that's a decent sample space.
I used this service as they were generally cheaper than others (USD5 per month) and because they had NRL channels. The NRL channels constantly go down or end up in a loop (and when reported they often say "there is no match on anyway" but I wanted the channel for more than just matches), so I ended up finding another provider with NRL channel in any case.
The Area 51 streams were so-so. I found I got less bufferring and definitely less channel down time with my other provider.
Area 51 have now announced a price hike to USD7/month, along with shutting down from the 20th to the 30th of December to apparently 'setup' the pay increase or some such. Their only communication around these were on their Discord - which is fair enough, it's their main communication channel. The shut down was announced and pinned (and then disappeared to the top of Announcements under a load of more current ones), the price hike spammed as an @Everyone message basically daily. But my invoice sent from them still said the due date was the 22nd (if they can spam messages in their Discord, surely they can amend invoices - or at least put a notice in them). Users only receive their invoice 5 days before the due date, so anybody who had a renew date between 25-30th it was impossible to renew for the Christmas period.
Further - they decided that when they said "shutting down from the 20th" they were referring to the 20th in New Zealand time? Meanwhile UK, US and basically every other country in the world it's still the 19th, yet they can't renew?
Anyway - long story short, now that they're USD7, I definitely don't recommend this service. Much more reliable streams in that price range.
I dropped A51 recently. It was pretty good but with other subs just don't really need it and I saw the price hike was coming. And it had more downtime than the others so I wasn't using it. For $5 TNT seems more reliable but with less channels. And there are so many others to try why not swap out the back up provider from time to time.