Even though I've been playing for quite a while, I've also had my fair share of breaks from the game, but I can confidently say that I've raided a majority of the raid tiers, either as a casual or semi-"hardcore". I gave up on WoD pretty early on which led me to skip every single **** up until HFC (in which I only attained AotC). . 
The experience which I consider relevant is as follows: (please note that I'm forgetting some info in regard to guilds and rank).

- Top 5 Lady Vashj and Kael'thas clears with <Eclipse> on Sylvanas.

- Partial Mythic progress in EN, NH and TOS. (5/7 , 6/9, 5/9), respectively. At this point in Legion I barely had a schedule that would let me attend 50% of the raids. I ended up not fully clearing any of those raids when they were the latest raid.

- Antorus, the Burning Throne - 11/11M. Late Cutting Edge, rank 1555 world with <Subject Zero>

- Uldir - 8/8M. CE. Rank 1180 world with <Exceed> (same guild, different name).

- BoD - 9/9M. CE. Rank 536 world with <Anguish>.

- CoS - 0/2M. <Anguish> close to a kill in Cabal. Guild gave up because of TEP. 

- Eternal Palace - 8/8M. CE. Progressed 7/8M with <Anguish> and then switched to <Sanctum Nocturnos> to finish the ****. I didn't, however, participate in their Azshara first kill. Rank 79 world.

- Ny'alotha - 12/12M. CE. Rank 133 world with <Sanctum Nocturnos>.
  
- Castle Nathria - 9/10M. CE. Rank 118 world with <Sanctum Nocturnos> and my first ever legitimately earned Hall of Famed (even though it's the scuffed HoA :). Missed the SLG kill because of personal issues but participated in every single raid apart from the last 2 leading to the kill (kill day included). Amassed a total of 250+ wipes but I still have no kill.

To note that I was part of the core raid team in every of the single raid listed above (the ones I considered relevant in the grand scheme of things). Played Tank and DPS along with several classes amongst all the raids, even though I've stuck to tanking and dpsing as DH as of late.