Personally I don't think it's worth it for one app. A firestick 4K with STB emulator plays better than anyother app or device for me and all it cost was 50 bucks.

According to the Mods on the Formuler forum the Z7 will continue to receive updates including the the latest MTVOL app . The Z8 as you said is untested and could be riddled with bugs just as the Z7 was on release

Buying for just the app.. get the Z7 its a no brainer

I just got the z7 and I love it. I had some issues with sound on an older TV, but works fine on my smart TV. I think the z7 has the best looking interface and navigation. It's fast, it never lags, and just as fast as my old cable box. Compared to the z8, I personally like the menu colors and interface skin on the z7. For some reason the z8 looks like a step backwards.

I haven't used z7+ but I can vouch for buzztv. People who haven't used buzz tv, can watch the review here. https://m.youtube.com/watch?v=-Hdcf3SEmIc

Specs 2gb ram, 8gb storage, Dual wifi, Android 7.1

Cost around ~$130 Cad

Will this app make its way to z7 will someone rip and extract it and see if it works. ?

I have a Zx / Z7+ and I just received my Z8 yesterday. Love my Formulers.