Hydra for T16 rifts too, being able to drop hydras and have them kill stuff while you loot chests etc. is nice.
For XP speed GRs, Tal’s all the way. It’s not particularly close.
For super speed GR90s for loot/shards/ low level gem levelling etc., hydra is a bit closer. In non-season, hydra actually easily beats Tal’s for GR90. That’s a little different this season though because the extra orb doesn’t work with pet kills, so it closes the gap between Tal’s Aether Walker Lightning Meteor (gets +1 orb) vs. hydra (no extra orb) in GR90.
I haven’t done a proper comparison with a time average for 10+ rifts to get a really good comparison, but I think they are much closer in S28 for GR90 speeds than they would normally be.
I’d probably just stick with Tal’s for all GRs though. Don’t even bother doing GR90 speeds, just do GR110 speeds with Tal’s + Aether Walker, or 120-130+ with Smoldering Core. Hydra may still be slightly faster for GR90, but Tal’s will get you way more XP/hour.
Tal variations are faster than hydra. I just press teleport in anything 110 and lower. Same with bounties. I’m clearing gr 120 in 90 seconds. Just need to practice it but more.
For pure xp tals gr 140 plus imo as less town time and high para I just farm 150s as I don’t enjoy speed and constant salvaging and occasionally get a good map to time attack rather than fishing and wasting keys