Just a brief report on our recent FRA-HER (Heraklion, Greece) -FRA trip with 4Y in business class.

Flights were booked as awards via the normal M&M website and showed up in the LH app. Check-In from there was forwarded to the 4Y website, worked well but boarding passes were not shown in the LH app. No 4Y app (good, not another LH family one...) Needed to store boarding passes in the wallet of the phone, which worked fine.
Lounge access in FRA without problem. Saw fellow passengers being driven to the plane by limo, so connecting F/HON services seem to work.
Cabin layout and seats exactly like LH, middle seat empty in C.
Meal service on the about 3h flight was better than LH: pre-flight drinks (water or a tasty passion fruit drink). Tasty food (sorry, forgot the pictures) both ways: starter, hot main and dessert. Full drinks selection incl hard liquor, warm cookie afterwards.
HER airport awfully crowded - they have way to little space for all the passengers being squeezed through. There is a lounge in the Schengen area operated by Sky Express. Very hidden - upstairs above low A gates and in the corner of a long corridor. Access rules seem confusing, I asked if they work with LH, assuming that rules apply for all LH family brands, which the friendly dragon declined. Starting the process of using my Priority Pass instead she noted that we were on 4Y and mentioned that they accept 4Y passengers (no LH, no EW). Nice! No spectacular lounge (food was very basic, no alcohol besides wine) but way nicer to sit there in peace than wait standing in the super crowded corridors outside.
Boarding processes in HER pretty chaotic - the layout of the gates makes priority boarding impossible. All gates are bus gates anyway - so no big difference.

All in all a good experience. Still, annoying that they have another brand with another website, another check-in process, another set of lounge access agreements. And all for paying their employees less than at LH, I assume.

Have safe travels

Primenumber