Worth noting that for the Boingo login can be a bit funny. I have now used it on around 4 EVA flights and a handful of other carriers.
It works fine on the computer but often on a mobile device, it may just display an unexpected error page (this seems to happen across all Deutsche Telekom airlines).
The easiest way is to reload the page in "desktop mode". On Android, it's a simple as selecting "Desktop site" from the dropdown menu. iOS is a little more difficult as it involves selecting the "resquest desktop site" but you need to do it at the right time (just after selecting Boingo login but before it's loaded).
Only Mastercard get access to the Boingo inflight roaming for free, other Boingo accounts have to pay $0.19 per minute once connected, so in that case, I'd just buy one of the EVA plans. My Speeds were fine the ping hovered around 800ms with an average download speed of 5mbps and a pathetic 0.07mbps upload.
Much faster than the OnAir service used by Emirates but much slower than a recent Cathay flight where unlimited data was US$20 for the flight and speeds were up to 46mbps download (when over Europe), this dropped back to 5-10mbps over Russia. Pings were a slightly faster 707ms and upload 0.7mbps - Cathay uses the new GoGo 2Ku service.