I've been a frequent user of Onair recently, and have the following observations...

I did use the free EID promotion on the A380 from DXB-BKK and it was quite slow, but usable. A number of seat mates nearby (in Y) also had their devices connected on the overnight flight so maybe it slowed it down some.

I'll definitely be on the lookout for the $1 deal though!

Recently I paid $20 for iPad connectivity from DXB-FRA and it was totally unusable, it kept dropping out, requiring frequent logins, and never could render complete webpages (in F on the A380). I emailed Onair customer service with my comments prior to landing and I received a refund before I landed^

So while Onair has some glitches and some growing pains yet to conquer, they do have good customer service!

It pays to remember that they are not affiliated directly with Emirates, and there is little the crew can do to improve the connectivity while in flight, but at least the OnAir customer service kept me as a frequent customer.